The SINGLE FLOWER (SFL) gene encodes a MYB transcription factor that regulates the number of flowers produced by the inflorescence of chickpea

Abstract

Summary Legumes usually have compound inflorescences, where flowers/pods develop from secondary inflorescences (I2), formed laterally at the primary inflorescence (I1). Number of flowers per I2, characteristic of each legume species, has important ecological and evolutionary relevance as it determines diversity in inflorescence architecture; moreover, it is also agronomically important for its potential impact on yield. Nevertheless, the genetic network controlling the number of flowers per I2 is virtually unknown. Chickpea (Cicer arietinum) typically produces one flower per I2 but single flower (sfl) mutants produce two (double‐pod phenotype). We isolated the SFL gene by mapping the sfl‐d mutation and identifying and characterising a second mutant allele. We analysed the effect of sfl on chickpea inflorescence ontogeny with scanning electron microscopy and studied the expression of SFL and meristem identity genes by RNA in situ hybridisation. We show that SFL corresponds to CaRAX1/2a, which codes a MYB transcription factor specifically expressed in the I2 meristem. Our findings reveal SFL as a central factor controlling chickpea inflorescence architecture, acting in the I2 meristem to regulate the length of the period for which it remains active, and therefore determining the number of floral meristems that it can produce.

SUPERMAN strikes again in legumes

“…Alternatively, they could show the emergence of new functions for transcription factors when they are expressed in species with different architectures. Recently, the SINGLE FLOWER ( SFL ) gene, a MYB transcription factor expressed in the I2, was shown to perform a similar role to MtSUP in chickpea ( Caballo et al., 2022 ). Multiflowered pea and chickpea mutants have been reported for three decades ( Murfet, 1985 ; Singer et al., 1999 ; Gaur and Gour, 2002 ; Srinivasan et al., 2006 ; Devi et al., 2018 ).…”

Phenotypic and Genetic Characterization of a Near-Isogenic Line Pair: Insights into Flowering Time in Chickpea.

“…The characteristics of NILs not only provide a focused study of owering time but also offer accessibility for exploring interconnected traits. In chickpea, NILs have successfully been applied in studies on growth habit [42], plant height [43], double/single pod [44,45], nodulation [46], Fusarium wilt resistance [47][48][49] as well as owering time [50].…”