Downregulation of polygalacturonase (PG) gene expression caused significant changes in gene expression in sesame (Sesamum indicum L.) false septa tissues.

Abstract

Sesame (Sesamum indicum L.) is one of the oldest cultivated oil crops worldwide and struggles with low yield, which could be attributed to capsule dehiscence and seed shattering just before and during full maturation. The present study addresses the seed-shattering in sesame via downregulating the endo-polygalacturonase (endo-PG) gene activity “known as the ripening enzyme”. Five lines of sesame plants using an RNAi transformation strategy via a non-tissue culture-based transformation technique. Individual transformants were tested using BASTA leave-painting and spraying over mature plants, as well as conducting PCR, RT-PCR, and real-time PCR tests on T1 plants. The transgenics exhibited a significant reduction in endo-PG levels and showed delays in leaves, organ senescence, and a delay in capsule opening. A transcriptome profiling study was conducted to understand the effect of downregulating the endo-PG expression levels on the genetic expression profile of false septa tissues excised from sesame capsules. Different comparisons between the expression profile of the false septa in transgenic vs non-transgenic control were conducted, yet we are reporting one of the comparisons in this study. A total of 24,468 unigenes were annotated, and 514 differentially expressed genes (DEGs) were detected in the selected comparison, including 349 up-regulated and 165 down-regulated unigenes. Nineteen DEGs for genes directly involved in plant hormones, cell wall modification, and capsule shattering were selected. Our results indicate that silencing the endo-PG gene caused changes in the expression of a wide range of genes, eventually leading to a dramatic reduction in seed-shattering in transgenic sesame capsules.