BnSIP1-1 Involves in Light Response and Regulation of Endogenous Hormones and Flowering Time of Brassica Napus

Abstract

BnSIP1-1 is a trihelix transcription factor family gene which functions in abiotic stress response and abscisic acid (ABA) signaling during seed germination and seedling growth of Brassica napus. In the present study, further sequence analysis and phenotype identification indicated that this gene had roles in light regulation and flowering of reproductive growth stage. Many phytohormones responsive cis-acting elements, including TC-rich repeats, GARE-motif, and TCA and TGA elements, were identified in the promoter sequence of BnSIP1-1. The expression of BnSIP1-1 was regulated by light period and remarkable higher expression level of BnSIP1-1 was detected in roots than in leaves. Overexpression of BnSIP1-1 in Arabidopsis delayed flowering time for 3–5 days in transgenic plants. In addition, we also found BnSIP1-1 can respond to abiotic and ABA stress (treated with 200 mM NaCl, 300 mM mannitol or 50 μM ABA for 0, 1, 6, and 24 h) in B. napus through adjusting not only ABA but also other endogenous hormones, including indole-3-acetic acid and salicylic acid. Moreover, jasmonates (JA) signaling pathway was found not involving in the pathway of BnSIP1-1 responding to abiotic stresses.

Conservation and Divergence of the Trihelix Genes in Brassica and Expression Profiles of BnaTH Genes in Brassica napus under Abiotic Stresses

“…With the release of the genome sequences of many plants, genome-wide identification of TH genes has been carried out in many species. However, other than for around 10 reported TH genes ( Table S10 ), the identification and the function of Brasscia TH genes, especially in B. napus , have not been well reported [ 5 , 16 , 17 , 18 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. In this study, a total of 455 TH genes was identified in six Brassica species and Arabidopsis , and the phylogenetic relationship, structure, cis -acting elements, chromosome distribution, gene duplication events, and collinearity were investigated.…”

Transcriptomic Profiling Highlights the ABA Response Role of BnSIP1-1 in Brassica napus

“…Positive T 3 generation plants were grown to produce cDNA libraries. The transgenic lines OE-7 and OE-27 overexpressing BnSIP1-1 were used for this study, in order to maintain consistency with previous research [ 13 , 24 ]. Lines OE-7 and OE-27 were used for phenotype characterization.…”

“…To have a better understanding how BnSIP1-1 reverses the trend of growth retardation caused by ABA in B. napus, tender seedlings were selected as the processing objects to obtain more sensitive data. Although there was no visible phenotype observed (Figure S1), we believed that many molecular level changes would be completely overturned based on our previous studies in BnSIP1-1-overexpressing B. napus [13,24]. Four-day-old seedlings of wildtype and transgenic plants treated with exogenous ABA were used for global transcriptomic analyses.…”

“…The trihelix family can be classified to five subfamilies, including GT1, GT2, SH4, GT γ , and SIP1 subfamilies [ 12 ]. To date, the trihelix family has been identified or expression profiled in more than 10 species [ 13 ]. For example, there are 30 and 52 trihelix genes in Arabidopsis thaliana ( A. thaliana ) and Brassica rapa ( B. rapa ) [ 14 ].…”