Transcriptome and functional analysis revealed the intervention of brassinosteroid in regulation of cold induced early flowering in tobacco

Abstract

Cold environmental conditions may often lead to the early flowering of plants, and the mechanism by cold-induced flowering remains poorly understood. Microscopy analysis in this study demonstrated that cold conditioning led to early flower bud differentiation in two tobacco strains and an Agilent Tobacco Gene Expression microarray was adapted for transcriptomic analysis on the stem tips of cold treated tobacco to gain insight into the molecular process underlying flowering in tobacco. The transcriptomic analysis showed that cold treatment of two flue-cured tobacco varieties (Xingyan 1 and YunYan 85) yielded 4176 and 5773 genes that were differentially expressed, respectively, with 2623 being commonly detected. Functional distribution revealed that the differentially expressed genes (DEGs) were mainly enriched in protein metabolism, RNA, stress, transport, and secondary metabolism. Genes involved in secondary metabolism, cell wall, and redox were nearly all up-regulated in response to the cold conditioning. Further analysis demonstrated that the central genes related to brassinosteroid biosynthetic pathway, circadian system, and flowering pathway were significantly enhanced in the cold treated tobacco. Phytochemical measurement and qRT-PCR revealed an increased accumulation of brassinolide and a decreased expression of the flowering locus c gene. Furthermore, we found that overexpression of NtBRI1 could induce early flowering in tobacco under normal condition. And low-temperature-induced early flowering in NtBRI1 overexpression plants were similar to that of normal condition. Consistently, low-temperature-induced early flowering is partially suppressed in NtBRI1 mutant. Together, the results suggest that cold could induce early flowering of tobacco by activating brassinosteroid signaling.

The Effects of Brassinosteroids on Nitrogen Utilization in Rice

“…The ensuing signal cascade is subsequently transduced downstream through a diverse array of protein families, including BSK kinases (OsBSKs), GSK3/SHAGGY-like kinases (OsGSKs), PPKL phosphatases (OsPPKLs), and BZR-family transcription factors (OsBZRs), involving intricate molecular processes such as phosphorylation and dephosphorylation [15][16][17][18][19]. Prevalent morphological traits exhibited by BR-deficient mutants across diverse species include their dwarf stature, compact architectural phenotype, and diminished size of various organs [15,20]. Moreover, some studies have indicated that applying BR during the rice booting stage can effectively maintain the content of nitrogen, phosphorus, and potassium in rice, delay chlorophyll degradation, and alleviate the effects of low-temperature stress [21].…”