Cytological, genetic, and proteomic analysis of a sesame (Sesamum indicum L.) mutant Siyl-1 with yellow–green leaf color

Abstract

AbstractBackgroundBoth photosynthetic pigments and chloroplasts in plant leaf cells play an important role in deciding on the photosynthetic capacity and efficiency in plants. Systematical investigating the regulatory mechanism of chloroplast development and chlorophyll (Chl) content variation is necessary for clarifying the photosynthesis mechanism for crops.ObjectiveThis study aims to explore the critical regulatory mechanism of leaf color mutation in a yellow–green leaf sesame mutantSiyl-1.MethodsWe performed the genetic analysis of the yellow-green leaf color mutation using the F2population of the mutantSiyl-1. We compared the morphological structure of the chloroplasts, chlorophyll content of the three genotypes of the mutant F2progeny. We performed the two-dimensional gel electrophoresis (2-DE) and compared the protein expression variation between the mutant progeny and the wild type.ResultsGenetic analysis indicated that there were 3 phenotypes of the F2population of the mutantSiyl-1, i.e.,YYtype with light-yellow leaf color (lethal);Yytype with yellow-green leaf color, andyytype with normal green leaf color. The yellow-green mutation was controlled by an incompletely dominant nuclear gene,Siyl-1. Compared with the wild genotype, the chloroplast number and the morphological structure inYYandYymutant lines varied evidently. The chlorophyll content also significantly decreased (P < 0.05). The 2-DE comparison showed that there were 98 differentially expressed proteins (DEPs) amongYY, Yy,andyylines. All the 98 DEPs were classified into 5 functional groups. Of which 82.7% DEPs proteins belonged to the photosynthesis and energy metabolism group.ConclusionThe results revealed the genetic character of yellow-green leaf color mutantSiyl-1. 98 DEPs were found inYYandYymutant compared with the wild genotype. The regulation pathway related with the yellow leaf trait mutation in sesame was analyzed for the first time. The findings supplied the basic theoretical and gene basis for leaf color and chloroplast development mechanism in sesame.