Both tobacco TA29 and sesame GN13 promoters provide tapetum-specific GUS expression in transgenic sesame (Sesamum indicum L.)
摘要
Low yield is one of the major concerns in sesame (Sesamum indicum L.) cultivation. Heterosis breeding is an alternate approach for improving sesame production compared to the time- and labour-consuming conventional breeding. However, tedious manual emasculation and pollination processes restrict the implementation of heterosis on sesame. The unavailability of male sterile, restorer, and maintainer lines further complicates the problem. The tapetum is a single-cell layer that encloses the sporangium of anthers and provides nutrition to the developing pollens. Biotechnological gene manipulation techniques can silence tapetum-specific pollen production gene(s) leading to male sterility. Studies with tapetum-specific genes are therefore crucial to reach such a goal. In this study, we have cloned two established tapetum-specific promoters: sesame SiBGproplus (hereafter GN13, NCBI accession no. KT246471) and tobacco TA29 (NCBI accession no. X52283) in the plant expression vector pCAMBIA2301 producing respective GN13::GUS and TA29::GUS recombinant vectors. We transformed sesame using conventional Agrobacterium-mediated transformation and recovered putatively transgenic T0 lines with 1.71% and 1.69% frequencies, respectively. The T0 lines were segregated at the 3:1 Mendelian segregation ratio for kanamycin resistance and generated T1 transgenic lines by self-fertilisation. Most of the T1 transgenics had a single copy of transgene integration. The histological assay revealed the tapetum-specific GUS expression in the T1 transgenic lines; GUS expression was undetected in other tested plant parts. Here we report for the first time, the successful tapetum-specific expression of GN13 and TA29 promoters in transgenic sesame lines. In further research, these promoters could be used for the biotechnological improvement of sesame.