Transcriptional Dynamics and Candidate Genes Involved in Pod Maturation of Common Bean (Phaseolus vulgaris L.).

Cristina Gómez-Martín,Ricardo Lebrón,Marta Santalla,Fernando J Yuste-Lisbona,Carmen Capel,Michael Hackenberg,Rafael Lozano,José L Oliver,Ana M González

doi:10.3390/plants9040545

Cristina Gómez-Martín, Ricardo Lebrón + Show 7 more

Open Access

https://doi.org/10.3390/plants9040545

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Abstract

Pod maturation of common bean relies upon complex gene expression changes, which in turn are crucial for seed formation and dispersal. Hence, dissecting the transcriptional regulation of pod maturation would be of great significance for breeding programs. In this study, a comprehensive characterization of expression changes has been performed in two common bean cultivars (ancient and modern) by analyzing the transcriptomes of five developmental pod stages, from fruit setting to maturation. RNA-seq analysis allowed for the identification of key genes shared by both accessions, which in turn were homologous to known Arabidopsis maturation genes and furthermore showed a similar expression pattern along the maturation process. Gene- expression changes suggested a role in promoting an accelerated breakdown of photosynthetic and ribosomal machinery associated with chlorophyll degradation and early activation of alpha-linolenic acid metabolism. A further study of transcription factors and their DNA binding sites revealed three candidate genes whose functions may play a dominant role in regulating pod maturation. Altogether, this research identifies the first maturation gene set reported in common bean so far and contributes to a better understanding of the dynamic mechanisms of pod maturation, providing potentially useful information for genomic-assisted breeding of common bean yield and pod quality attributes.

Highlights

Despite the differences between dry and fleshy fruit developmental patterns, strong similarities have been found in the molecular circuits governing their development and maturation programs, indicating that fruit regulatory networks are conserved across a broad spectrum of angiosperms [1,2]
Jasmonate promotes senescence and plays an important role in chlorophyll degradation [12,13], which is synthesized from alpha-linolenic acid [14,15], suggesting that the accumulation of this acid during maturation is responsible for stimulating chlorophyll loss [16]
A comprehensive transcriptome analysis of pod development has been performed in two contrasting accessions of common bean with the aim to reveal those gene expression changes that, independently of the genotype diversity, are involved in the maturation process of common bean

Summary

Introduction

Despite the differences between dry and fleshy fruit developmental patterns, strong similarities have been found in the molecular circuits governing their development and maturation programs, indicating that fruit regulatory networks are conserved across a broad spectrum of angiosperms [1,2]. Among these conserved physiological and metabolic processes, the decay on photosynthesis and translation ribosome machinery led to the deactivation of green stage-related processes and the production of secondary color. The increased accumulation of antioxidant and monoterpene is an important feature of the fruit maturation process [17,18,19]

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