PLANT SIGNALING & BEHAVIOR 2016, VOL. 11, NO. 7, e1197467 (3 pages) http://dx.doi.org/10.1080/15592324.2016.1197467
SHORT COMMUNICATION
The single evolutionary origin of chlorinated auxin provides a phylogenetically informative trait in the Fabaceae Hong Kiat Lam, John J. Ross, Erin L. McAdam, and Scott A. M. McAdam School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
ABSTRACT
ARTICLE HISTORY
Chlorinated auxin (4-chloroindole-3-acetic acid, 4-Cl-IAA), a highly potent plant hormone, was once thought to be restricted to species of the tribe Fabeae within the Fabaceae, until we recently detected this hormone in the seeds of Medicago, Melilotus and Trifolium species. The absence of 4-Cl-IAA in the seeds of the cultivated species Cicer aeritinum from the Cicerae tribe, immediately basal to the Fabeae and Trifolieae tribes, suggested a single evolutionary origin of 4-Cl-IAA. Here, we provide a more robust phylogenetic placement of the ability to produce chlorinated auxin by screening key species spanning this evolutionary transition. We report no detectable level of 4-Cl-IAA in Cicer echinospermum (a wild relative of C. aeritinum) and 4 species (Galega officinalis, Parochetus communis, Astragalus propinquus and A. sinicus) from tribes or clades more basal or sister to the Cicerae tribe. We did detect 4-Cl-IAA in the dry seeds of 4 species from the genus Ononis that are either basal to the genera Medicago, Melilotus and Trigonella or basal to, but still within, the Fabeae and Trifolieae (ex. Parochetus) clades. We conclude that the single evolutionary origin of this hormone in seeds can be used as a phylogenetically informative trait within the Fabaceae.
Received 11 May 2016 Revised 25 May 2016 Accepted 27 May 2016
Chlorinated auxin (4-chloroindole-3-acetic acid, 4-Cl-IAA was first detected in the immature seeds of Pisum sativum by Gandar and Nitsch1 and Marumo et al.2 The potency of this auxin has been demonstrated in various auxin bioassays.3 Recent metabolism experiments demonstrated that 4-Cl-IAA is synthesized via a chlorinated version of the indole-3-pyruvate pathway, the main tryptophan-dependent IAA synthesis pathway operating in pea seeds.4 The growth regulatory role of chlorinated auxin is thought to involve the induction of GA biosynthesis and the inhibition of ethylene action on early pericarp growth and elongation.5 The phylogenetic distribution and evolutionary origins of this hormone, however, have received little attention. Our recent discovery of 4-Cl-IAA in the seeds of Medicago truncatula, Melilotus indicus and 3 Trifolium species has pushed the number of recognized 4-ClIAA-producing leguminous species to 14 and extended our detection of this hormone beyond species of the tribe Fabeae, to which this hormone was previously thought to be restricted.6 It is surprising that the ability of these species to produce chlorinated auxin had remained unrecognised, given that clovers (Trifolium species) have a long cultivation history due to their agricultural significance, especially in temperate regions as forage crops7; and that Medicago truncatula is a model species with a sequenced genome. While the phylogenetic relationships of taxa within the Fabaceae have been somewhat enigmatic, the reconstruction of a phylogeny based on the analysis of the
KEYWORDS
Auxin; chlorinated auxin (4-Cl-IAA; Cicerae; evolution; Fabaceae; Fabeae; Ononis; phylogeny; seeds; Trifolieae
plastid MATK gene resolves many well-supported subclades within the legume family.8 We have utilised this greater resolution and clade support to investigate the evolutionary origin of 4-Cl-IAA in this family. Our data strongly indicate that after the divergence of the genus Cicer from the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes, chlorination capacity evolved once, approximately 25 million years ago.6 Determination of the precise evolutionary origin of 4-Cl-IAA in our previous study was based on the inability to detect this hormone in a single cultivated species from the Cicerae tribe (Cicer aeritinum), which we took as a sole representative of the clade immediately basal to the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes.6 However, there are a number of genera that are closely related to the Fabeae and Trifolieae, according to modern phylogenic relationships in the Fabaceae.8,9 The closest of these is the genus Galega which is either sister to Cicer or immediately basal to Cicer (Fig. 1). Basal to this clade is the monospecific genus Parochetus, traditionally and paraphyletically long assigned to the Trifolieae, followed by the Astragalean clade (for which we included Clianthus puniceus as a representative of in our previous study) (Fig. 1). In order to definitively demonstrate a single evolutionary origin in the common ancestor of the Fabeae and Trifolieae, (ex. Parochetus) tribes we analyzed dry seed extracts from the perennial species C. echinospermum (a wild relative of C. aeritinum), Galega officinalis, Parochetus communis and 2
CONTACT Scott A. M. McAdam [email protected] Addendum to: Lam HK, McAdam SAM, McAdam EL, Ross JJ. (2015) Evidence that chlorinated auxin is restricted to the Fabaceae but not to the Fabeae. Plant Physiology 168: 798-803. http://dx.doi.org/10.1104/pp.15.00410 © 2016 Taylor & Francis Group, LLC
e1197467-2
H. K. LAM ET AL.
Figure 1. Phylogeny of the major lineages of the inverted-repeat-loss clade (IRLC) of the family Fabaceae with a particular focus on the closest lineages to the tribe Fabeae. The ability to produce 4-Cl-IAA appears to have evolved after the divergence of the genera Cicer and Galega approximately 25 million years ago (indicated by arrow and red brances). Species with detectable 4-Cl-IAA are shown in red; species that do not have detectable 4-Cl-IAA are shown in black. Species investigated in this study are indicated by an asterisk. Phylogenetic relationships and divergence dates are taken from Choi. et al.,14 Lavin et al.,9 Schaefer et al.10 and Wojciechowski et al.8
additional species within the Astragalean clade (Astragalus sinicus and A. propinquus) using base hydrolysis (to hydrolyse auxin conjugates) and UPLC-MS/MS as described previously.6 Chlorinated auxin was not detected in any of these species (Table 1), although all contained IAA, with the level in P. communis being remarkably high (Table 1). To confirm the single evolutionary origin of 4-Cl-IAA within the Fabeae and Trifolieae (ex. Parochetus) tribes, we also sourced 4 species of Ononis, a genus that may be either basal to the genera Medicago, Melilotus and Trigonella 8,9 or basal to the entire Fabeae and Trifolieae (ex. Parochetus) clades,10 and which, as a genus, has not yet been tested for auxins in seeds (Fig. 1). The species tested here included O. fruticosa, O. natrix, O. repens and O. spinosa. All four species not only contained endogenous chlorinated auxins but also recorded very high levels, ranging from 1381 ng g¡1 (O. fruticosa) to 6261 ng g¡1 (O. repens) (Table 1). These results show good congruence with our previous study and provide stronger evidence for our observation that the chlorinating ability arose along with the divergence of the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes (Fig. 1). A complete survey of Fabaceae (or indeed angiosperm) species containing 4-Cl-IAA would be intriguing, but also highly ambitious as approximately 800 species (from the genera Table 1. Endogenous levels of 4-Cl-IAA and IAA in 15 representative species from the family Fabaceae. (n.d., not detected). Species
Phylogenetic clade
Ononis fruticosa Ononis natrix Ononis repens Ononis spinosa Cicer echinospermum Galega officinalis Parochetus communis Astragalus propinquus Astragalus sinicus
Trifolieae Trifolieae Trifolieae Trifolieae Cicereae Trifolieae Trifolieae Astragalae Astragalae
Tissue type
IAA (ng.g¡1)
4-Cl-IAA (ng.g ¡1)
Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds
3059 3741 3555 2016 7139 428 39235 5425 461
1381 3600 6261 4144 n.d. n.d. n.d. n.d. n.d.
Pisum, Lathyrus, Lens, Medicago, Trifolium, Melilotus and Vicia) within this chlorinating clade remain unexamined and species collection, sourcing and routine screening can be difficult. The ability to chlorinate has not yet been examined in species from 2 remaining genera within the Fabeae and Trifolieae (ex. Parochetus) tribes, namely Trigonella and Vavilovia. The genus Trigonella is sister to the genus Melilotus (which has 4-Cl-IAA) and has between 70 and 128 species11 including fenugreek (Trigonella foenum-graecum), an agriculturally important crop and popular spice. In contrast, only a single species comprises the genus Vavilovia of the tribe Fabeae, V. formosa, which is hailed as a relict, endangered species and is basal to the genera Pisum and Lathyrus.12,13 Observations of species spanning all of the genera, clades and subgenera within the Fabeae and Trifolieae (ex. Parochetus) tribes will help us to reveal how stable or labile the evolution of chlorinating ability has been in this clade. In conclusion, the number of leguminous species with known chlorinating capability now stands at 18 and encompasses species from both the Fabeae and Trifolieae tribes. With the results accrued, we can be increasingly confident that the capacity to produce chlorinated auxin has a single evolutionary origin, most likely in the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes that evolved after the divergence of Cicer and Galega, 25 million years ago. In addition, our data suggest that the ability to chlorinate auxin can be used as a phylogenetically informative trait within the Fabaceae. A pertinent example emerging from our present study is the lack of 4-Cl-IAA in the seeds of P. communis, a species traditionally assigned to the tribe Trifolieae. Our data support the conclusion reached by molecular studies,8,9 that Parochetus is not a member of the Trifolieae tribe and diverged before the evolution of this clade, as all other Trifolieae species so far examined contain 4-Cl-IAA.
Disclosure of potential confllicts of interest No potential conflicts of interest were disclosed.
PLANT SIGNALING & BEHAVIOR
References 1. Gandar J, Nitsch C. Isolement de l’ester methylique d’un acide chloro3-indolylacetique a partir de graines immatures de pois, Pisum sativum. C R Acad Sci 1967; 265:1795-8; 2. Marumo S, Hattori H, Abe H, Munakata K. Isolation of 4-chloroindolyl-3-acetic acid from immature seeds of Pisum sativum. Nature 1968; 219: 959-960 3. Reinecke DM. 4-Chloroindole-3-acetic acid and plant growth. Plant Growth Regul 1999; 27:3-13; http://dx.doi.org/10.1023/ A:1006191917753 4. Tivendale ND, Davidson SE, Davies NW, Smith JA, Dalmais M, Bendahmane AI, Quittenden LJ, Sutton L, Bala RK, Le Signor C, Thompson R, Horne J, Reid JB, Ross JJ. Biosynthesis of the halogenated auxin, 4chloroindole-3-acetic acid. Plant Physiol 2012; 159:1055-63; PMID:22573801; http://dx.doi.org/10.1104/pp.112.198457 5. Johnstone MMG, Reinecke DM, Ozga JA. The auxins IAA and 4-ClIAA differentially modify gibberellin action via ethylene response in developing pea fruit. J Plant Growth Regul 2005; 24:214-25; http://dx. doi.org/10.1007/s00344-005-0035-9 6. Lam HK, McAdam SAM, McAdam EL, Ross JJ. Evidence that chlorinated auxin is restricted to the Fabaceae but not to the Fabeae. Plant Physiol 2015; 168:798-803; PMID:25971549; http://dx.doi.org/ 10.1104/pp.15.00410 7. Smykal P, Coyne CJ, Ambrose MJ, Maxted N, Schaefer H, Blair MW, Berger J, Greene SL, Nelson MN, Besharat N. Legume crops phylogeny and genetic diversity for science and breeding. Cr Rev Plant Sci 2015; 34:43-104; http://dx.doi.org/10.1080/ 07352689.2014.897904
e1197467-3
8. Wojciechowski MF, Lavin M, Sanderson MJ. A phylogeny of legumes (Leguminosae) based on analysis of the plastid matK gene resolves many well-supported subclades within the family. Am J Bot 2004; 91:1846-62; PMID:21652332; http://dx.doi.org/10.3732/ajb.91.11.1846 9. Lavin M, Herendeen PS, Wojciechowski MF. Evolutionary rates analysis of Leguminosae implicates a rapid diversification of lineages during the Tertiary. Syst Biol 2005; 54:575-94; PMID:16085576; http://dx. doi.org/10.1080/10635150590947131 10. Schaefer H, Hechenleitner P, Santos-Guerra A, de Sequeira MM, Pennington RT, Kenicer G, Carine MA. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages. BMC Evol Biol 2012; 12:250; PMID:23267563; http://dx.doi.org/10.1186/1471-2148-12-250 11. Petropoulos GA. Fenugreek: the genus Trigonella, Taylor and Francis, New York 2002; ISBN 9780415296571 12. Mikic A, Smykal P, Kenicer G, Vishnyakova M, Sarukhanyan N, Akopian J, Vanyan A, Gabrielyan I, Smykalova I, Sherbakova E. The bicentenary of the research on ‘beautiful’ vavilovia (Vavilovia formosa), a legume crop wild relative with taxonomic and agronomic potential. Bot J Linn Soc 2013; 172:524-31; http://dx.doi.org/10.1111/boj.12060 13. Oskoueiyan R, Osaloo SK, Maassoumi AA, Nejadsattari T, Mozaffarian V. Phylogenetic status of Vavilovia formosa (Fabaceae-Fabeae) based on nrDNA ITS and cpDNA sequences. Biochem Syst Ecol 2010; 38:313-9; http://dx.doi.org/10.1016/j. bse.2010.01.011 14. Choi H-K, Mun J-H, Kim D-J, Zhu H, Baek J-M, Mudge J, Roe B, Ellis N, Doyle J, Kiss GB. Estimating genome conservation between crop and model legume species. P Natl Acad Sci USA 2004; 101:15289-94; PMID:15489274; http://dx.doi.org/10.1073/pnas.0402251101
SHORT COMMUNICATION
The single evolutionary origin of chlorinated auxin provides a phylogenetically informative trait in the Fabaceae Hong Kiat Lam, John J. Ross, Erin L. McAdam, and Scott A. M. McAdam School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
ABSTRACT
ARTICLE HISTORY
Chlorinated auxin (4-chloroindole-3-acetic acid, 4-Cl-IAA), a highly potent plant hormone, was once thought to be restricted to species of the tribe Fabeae within the Fabaceae, until we recently detected this hormone in the seeds of Medicago, Melilotus and Trifolium species. The absence of 4-Cl-IAA in the seeds of the cultivated species Cicer aeritinum from the Cicerae tribe, immediately basal to the Fabeae and Trifolieae tribes, suggested a single evolutionary origin of 4-Cl-IAA. Here, we provide a more robust phylogenetic placement of the ability to produce chlorinated auxin by screening key species spanning this evolutionary transition. We report no detectable level of 4-Cl-IAA in Cicer echinospermum (a wild relative of C. aeritinum) and 4 species (Galega officinalis, Parochetus communis, Astragalus propinquus and A. sinicus) from tribes or clades more basal or sister to the Cicerae tribe. We did detect 4-Cl-IAA in the dry seeds of 4 species from the genus Ononis that are either basal to the genera Medicago, Melilotus and Trigonella or basal to, but still within, the Fabeae and Trifolieae (ex. Parochetus) clades. We conclude that the single evolutionary origin of this hormone in seeds can be used as a phylogenetically informative trait within the Fabaceae.
Received 11 May 2016 Revised 25 May 2016 Accepted 27 May 2016
Chlorinated auxin (4-chloroindole-3-acetic acid, 4-Cl-IAA was first detected in the immature seeds of Pisum sativum by Gandar and Nitsch1 and Marumo et al.2 The potency of this auxin has been demonstrated in various auxin bioassays.3 Recent metabolism experiments demonstrated that 4-Cl-IAA is synthesized via a chlorinated version of the indole-3-pyruvate pathway, the main tryptophan-dependent IAA synthesis pathway operating in pea seeds.4 The growth regulatory role of chlorinated auxin is thought to involve the induction of GA biosynthesis and the inhibition of ethylene action on early pericarp growth and elongation.5 The phylogenetic distribution and evolutionary origins of this hormone, however, have received little attention. Our recent discovery of 4-Cl-IAA in the seeds of Medicago truncatula, Melilotus indicus and 3 Trifolium species has pushed the number of recognized 4-ClIAA-producing leguminous species to 14 and extended our detection of this hormone beyond species of the tribe Fabeae, to which this hormone was previously thought to be restricted.6 It is surprising that the ability of these species to produce chlorinated auxin had remained unrecognised, given that clovers (Trifolium species) have a long cultivation history due to their agricultural significance, especially in temperate regions as forage crops7; and that Medicago truncatula is a model species with a sequenced genome. While the phylogenetic relationships of taxa within the Fabaceae have been somewhat enigmatic, the reconstruction of a phylogeny based on the analysis of the
KEYWORDS
Auxin; chlorinated auxin (4-Cl-IAA; Cicerae; evolution; Fabaceae; Fabeae; Ononis; phylogeny; seeds; Trifolieae
plastid MATK gene resolves many well-supported subclades within the legume family.8 We have utilised this greater resolution and clade support to investigate the evolutionary origin of 4-Cl-IAA in this family. Our data strongly indicate that after the divergence of the genus Cicer from the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes, chlorination capacity evolved once, approximately 25 million years ago.6 Determination of the precise evolutionary origin of 4-Cl-IAA in our previous study was based on the inability to detect this hormone in a single cultivated species from the Cicerae tribe (Cicer aeritinum), which we took as a sole representative of the clade immediately basal to the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes.6 However, there are a number of genera that are closely related to the Fabeae and Trifolieae, according to modern phylogenic relationships in the Fabaceae.8,9 The closest of these is the genus Galega which is either sister to Cicer or immediately basal to Cicer (Fig. 1). Basal to this clade is the monospecific genus Parochetus, traditionally and paraphyletically long assigned to the Trifolieae, followed by the Astragalean clade (for which we included Clianthus puniceus as a representative of in our previous study) (Fig. 1). In order to definitively demonstrate a single evolutionary origin in the common ancestor of the Fabeae and Trifolieae, (ex. Parochetus) tribes we analyzed dry seed extracts from the perennial species C. echinospermum (a wild relative of C. aeritinum), Galega officinalis, Parochetus communis and 2
CONTACT Scott A. M. McAdam [email protected] Addendum to: Lam HK, McAdam SAM, McAdam EL, Ross JJ. (2015) Evidence that chlorinated auxin is restricted to the Fabaceae but not to the Fabeae. Plant Physiology 168: 798-803. http://dx.doi.org/10.1104/pp.15.00410 © 2016 Taylor & Francis Group, LLC
e1197467-2
H. K. LAM ET AL.
Figure 1. Phylogeny of the major lineages of the inverted-repeat-loss clade (IRLC) of the family Fabaceae with a particular focus on the closest lineages to the tribe Fabeae. The ability to produce 4-Cl-IAA appears to have evolved after the divergence of the genera Cicer and Galega approximately 25 million years ago (indicated by arrow and red brances). Species with detectable 4-Cl-IAA are shown in red; species that do not have detectable 4-Cl-IAA are shown in black. Species investigated in this study are indicated by an asterisk. Phylogenetic relationships and divergence dates are taken from Choi. et al.,14 Lavin et al.,9 Schaefer et al.10 and Wojciechowski et al.8
additional species within the Astragalean clade (Astragalus sinicus and A. propinquus) using base hydrolysis (to hydrolyse auxin conjugates) and UPLC-MS/MS as described previously.6 Chlorinated auxin was not detected in any of these species (Table 1), although all contained IAA, with the level in P. communis being remarkably high (Table 1). To confirm the single evolutionary origin of 4-Cl-IAA within the Fabeae and Trifolieae (ex. Parochetus) tribes, we also sourced 4 species of Ononis, a genus that may be either basal to the genera Medicago, Melilotus and Trigonella 8,9 or basal to the entire Fabeae and Trifolieae (ex. Parochetus) clades,10 and which, as a genus, has not yet been tested for auxins in seeds (Fig. 1). The species tested here included O. fruticosa, O. natrix, O. repens and O. spinosa. All four species not only contained endogenous chlorinated auxins but also recorded very high levels, ranging from 1381 ng g¡1 (O. fruticosa) to 6261 ng g¡1 (O. repens) (Table 1). These results show good congruence with our previous study and provide stronger evidence for our observation that the chlorinating ability arose along with the divergence of the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes (Fig. 1). A complete survey of Fabaceae (or indeed angiosperm) species containing 4-Cl-IAA would be intriguing, but also highly ambitious as approximately 800 species (from the genera Table 1. Endogenous levels of 4-Cl-IAA and IAA in 15 representative species from the family Fabaceae. (n.d., not detected). Species
Phylogenetic clade
Ononis fruticosa Ononis natrix Ononis repens Ononis spinosa Cicer echinospermum Galega officinalis Parochetus communis Astragalus propinquus Astragalus sinicus
Trifolieae Trifolieae Trifolieae Trifolieae Cicereae Trifolieae Trifolieae Astragalae Astragalae
Tissue type
IAA (ng.g¡1)
4-Cl-IAA (ng.g ¡1)
Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds Dry seeds
3059 3741 3555 2016 7139 428 39235 5425 461
1381 3600 6261 4144 n.d. n.d. n.d. n.d. n.d.
Pisum, Lathyrus, Lens, Medicago, Trifolium, Melilotus and Vicia) within this chlorinating clade remain unexamined and species collection, sourcing and routine screening can be difficult. The ability to chlorinate has not yet been examined in species from 2 remaining genera within the Fabeae and Trifolieae (ex. Parochetus) tribes, namely Trigonella and Vavilovia. The genus Trigonella is sister to the genus Melilotus (which has 4-Cl-IAA) and has between 70 and 128 species11 including fenugreek (Trigonella foenum-graecum), an agriculturally important crop and popular spice. In contrast, only a single species comprises the genus Vavilovia of the tribe Fabeae, V. formosa, which is hailed as a relict, endangered species and is basal to the genera Pisum and Lathyrus.12,13 Observations of species spanning all of the genera, clades and subgenera within the Fabeae and Trifolieae (ex. Parochetus) tribes will help us to reveal how stable or labile the evolution of chlorinating ability has been in this clade. In conclusion, the number of leguminous species with known chlorinating capability now stands at 18 and encompasses species from both the Fabeae and Trifolieae tribes. With the results accrued, we can be increasingly confident that the capacity to produce chlorinated auxin has a single evolutionary origin, most likely in the common ancestor of the Fabeae and Trifolieae (ex. Parochetus) tribes that evolved after the divergence of Cicer and Galega, 25 million years ago. In addition, our data suggest that the ability to chlorinate auxin can be used as a phylogenetically informative trait within the Fabaceae. A pertinent example emerging from our present study is the lack of 4-Cl-IAA in the seeds of P. communis, a species traditionally assigned to the tribe Trifolieae. Our data support the conclusion reached by molecular studies,8,9 that Parochetus is not a member of the Trifolieae tribe and diverged before the evolution of this clade, as all other Trifolieae species so far examined contain 4-Cl-IAA.
Disclosure of potential confllicts of interest No potential conflicts of interest were disclosed.
PLANT SIGNALING & BEHAVIOR
References 1. Gandar J, Nitsch C. Isolement de l’ester methylique d’un acide chloro3-indolylacetique a partir de graines immatures de pois, Pisum sativum. C R Acad Sci 1967; 265:1795-8; 2. Marumo S, Hattori H, Abe H, Munakata K. Isolation of 4-chloroindolyl-3-acetic acid from immature seeds of Pisum sativum. Nature 1968; 219: 959-960 3. Reinecke DM. 4-Chloroindole-3-acetic acid and plant growth. Plant Growth Regul 1999; 27:3-13; http://dx.doi.org/10.1023/ A:1006191917753 4. Tivendale ND, Davidson SE, Davies NW, Smith JA, Dalmais M, Bendahmane AI, Quittenden LJ, Sutton L, Bala RK, Le Signor C, Thompson R, Horne J, Reid JB, Ross JJ. Biosynthesis of the halogenated auxin, 4chloroindole-3-acetic acid. Plant Physiol 2012; 159:1055-63; PMID:22573801; http://dx.doi.org/10.1104/pp.112.198457 5. Johnstone MMG, Reinecke DM, Ozga JA. The auxins IAA and 4-ClIAA differentially modify gibberellin action via ethylene response in developing pea fruit. J Plant Growth Regul 2005; 24:214-25; http://dx. doi.org/10.1007/s00344-005-0035-9 6. Lam HK, McAdam SAM, McAdam EL, Ross JJ. Evidence that chlorinated auxin is restricted to the Fabaceae but not to the Fabeae. Plant Physiol 2015; 168:798-803; PMID:25971549; http://dx.doi.org/ 10.1104/pp.15.00410 7. Smykal P, Coyne CJ, Ambrose MJ, Maxted N, Schaefer H, Blair MW, Berger J, Greene SL, Nelson MN, Besharat N. Legume crops phylogeny and genetic diversity for science and breeding. Cr Rev Plant Sci 2015; 34:43-104; http://dx.doi.org/10.1080/ 07352689.2014.897904
e1197467-3
8. Wojciechowski MF, Lavin M, Sanderson MJ. A phylogeny of legumes (Leguminosae) based on analysis of the plastid matK gene resolves many well-supported subclades within the family. Am J Bot 2004; 91:1846-62; PMID:21652332; http://dx.doi.org/10.3732/ajb.91.11.1846 9. Lavin M, Herendeen PS, Wojciechowski MF. Evolutionary rates analysis of Leguminosae implicates a rapid diversification of lineages during the Tertiary. Syst Biol 2005; 54:575-94; PMID:16085576; http://dx. doi.org/10.1080/10635150590947131 10. Schaefer H, Hechenleitner P, Santos-Guerra A, de Sequeira MM, Pennington RT, Kenicer G, Carine MA. Systematics, biogeography, and character evolution of the legume tribe Fabeae with special focus on the middle-Atlantic island lineages. BMC Evol Biol 2012; 12:250; PMID:23267563; http://dx.doi.org/10.1186/1471-2148-12-250 11. Petropoulos GA. Fenugreek: the genus Trigonella, Taylor and Francis, New York 2002; ISBN 9780415296571 12. Mikic A, Smykal P, Kenicer G, Vishnyakova M, Sarukhanyan N, Akopian J, Vanyan A, Gabrielyan I, Smykalova I, Sherbakova E. The bicentenary of the research on ‘beautiful’ vavilovia (Vavilovia formosa), a legume crop wild relative with taxonomic and agronomic potential. Bot J Linn Soc 2013; 172:524-31; http://dx.doi.org/10.1111/boj.12060 13. Oskoueiyan R, Osaloo SK, Maassoumi AA, Nejadsattari T, Mozaffarian V. Phylogenetic status of Vavilovia formosa (Fabaceae-Fabeae) based on nrDNA ITS and cpDNA sequences. Biochem Syst Ecol 2010; 38:313-9; http://dx.doi.org/10.1016/j. bse.2010.01.011 14. Choi H-K, Mun J-H, Kim D-J, Zhu H, Baek J-M, Mudge J, Roe B, Ellis N, Doyle J, Kiss GB. Estimating genome conservation between crop and model legume species. P Natl Acad Sci USA 2004; 101:15289-94; PMID:15489274; http://dx.doi.org/10.1073/pnas.0402251101
