The Screening And Verification Of Photoperiodic Flowering Genes In Soybean

Soybean[Glycine max (L) Merr.] is one of the major oil crops and important source of plant protein. Soybean(Glycine max) is a facultative short-day plant with a sensitive photoperiod perception and reaction system, which allows it to adjust its physiological state and gene regulatory networks to seasonal and diurnal changes in environmental conditions. The wide adaptability of soybean has been created by natural variation in the major genes and quantitative trait loci controlling flowering. However, the cultivation area of each cultivar is restricted to a very narrow range of latitudes, which threaten to breed wide-adaptability soybean cultivars. The circadian clock system that controls genes and proteins is indispensable for photoperiodic flowering and not clear in soybean. Here, I applied RNAseq to identify the rhythmic genes in the purposes of interpreting regulatory network of photoperiodic flowering in soybean. Through JTK-CYCLE algorithm,16616 genes were identified to show rhythmic pattern and 14799 and 8957 genes were present in rhythmic pattern under long-day or short-day conditions, respectively.7140 genes were identified to exhibit in rhythmic pattern under both long-day and short-day conditions.7659 genes were specifically expressed under the long-day conditions and 1817 genes were specifically expressed under the short-day conditions. The core oscillator genes in Arabidopsis and soybean are conserved. Some of soybean homologs of Arabidopsis flowering genes exhibited different transcriptional levels under long-day and short-day conditions, which indicates those genes may be involved in the regulation of flowering in soybean. Furthermore, through the comparison of peak expression levels of genes under the long-day and short-day conditions, I identified differently-expressed genes that may contribute to photoperiodic responses. Finally, virus induced gene silencing through BPMV were applied to knockdown the those differently-expressed genes to understand the functions of the genes.