Molecular tagging of photoperiod responsive flowering in Indian bean [Lablab purpureus (L.) Sweet] Vinita Ramtekey*, Arpit Bhuriya, Dipendra Ayer, Vipulkumar Parekh, Kaushal Modha, Bhushan Kale, Gopal Vadodariya and Ritesh Patel (

Abstract

Photoperiod responsive flowering and growth habit might have played a key role in domestication of lablab bean (Lablab purpureus) and currently shifting its cultivation from intercropping to monoculture. Most of the landraces of lablab bean exhibit photoperiod sensitivity in flowering and indeterminate growth habit. A cross was made between GNIB21 and GP189 which are phenotypic extremes for photoperiod responsive flowering. The F1 hybrid exhibited dominant traits like indeterminate growth habit and photosensitive flowering endowed from male parent. Segregation pattern of 3:1 in F2 generation indicated monogenic recessive nature of photoperiod insensitive flowering. Bulk segregant analysis in F2 population revealed association of PvTFLy1, a locus governing determinate growth habit in lablab bean, with photoperiod responsive flowering where an amplicon of 300 bp was observed in photo sensitive GP189 while it was absent in photo insensitive variety GNIB21. Significant ÷2 test indicated coupling phase of linkage between PvTFLY1 and photoperiod responsive flowering. Linkage analysis placed PvTFLY1 at the distance of 19.23 cM from the locus governing photoperiod responsive flowering. The linkage between growth habit and photoperiod responsive flowering in common bean, soybean and Indian bean suggest that these traits may be governed by mutation or deletion of E3 (or GmPhyA3) and Dt1 homologs in Indian bean. Information available on characterized genes for photoperiod responsive flowering and determinate growth habit from common bean, soybean and other related legumes may be utilized for isolation, characterization, mapping and molecular dissection of genes involved in regulation of photoperiod responsive flowering in Indian bean.

Allelic characterization and protein structure analysis reveals the involvement of splice site mutation for growth habit differences in Lablab purpureus (L.) Sweet

“…Two orthologs of pea TFL1a , GmTFL1a and GmTFL1b , were isolated from the soybean through molecular dissection; mapping analysis indicated that GmTFL1b was a candidate for Dt1 [ 45 ] . Cosegregation of the marker and TFL locus indicated that LprTFL is a homologue of the TFL1 in Indian bean [ 6 ].…”

“…A linkage relationship between growth habit and flowering homologues has been reported in soybean [ 52 , 53 ], pea [ 19 ] and common bean [ 2 ]. Linkage between growth habit and photoperiod-responsive flowering has been reported in Indian bean [ 5 , 6 ]. Two FT homologues GmFT2a and GmFT5a were found to be involved in the control of photoperiodic flowering in soybean [ 54 ].…”

“…To identify homologous sequence of TFL in Indian bean through candidate gene approach, the sequence was obtained from linkage study in Indian bean [ 6 ]. Basic Local Alignment Search Tool (BLAST) analysis showed its homology with the locus controlling flowering behaviour in common bean PvTFL1y (genotype G22833; accession JN418237.1) .…”

“…Results of F 2 populations indicated that growth habit is governed by three genes GH 1 , GH 2 and GH 3 , of which, two are complementary with dominance of indeterminate growth habit [ 5 ]. Determinate growth habit and photoperiod-insensitive flowering are linked in Indian bean [ 3 , 6 ]. No efforts have been made in Indian bean for molecular dissection of growth habit and flowering.…”

“…Study in the Indian bean with PvTFL1y- specific primers showed the association of this marker with growth habit [ 6 ]. The present study aimed to identify, characterize and validate a locus responsible for growth habit in Indian bean utilizing candidate gene approach coupled with sequencing and protein modelling.…”