Virus induced gene silencing (VIGS) for functional analysis of wheat TaPCNA participated in apoptosis exposed to enhanced UV-B radiation

Abstract Background:Plant cell apoptosis is manifested by breakage of cellular DNA and changes of membrane permeability which caused physiological metabolism disturbance and growth inhibition. Besides, the UV-B radiation inhibits plant growth and DNA break. The PCNA (Proliferating Cell Nuclear Antigen) is an important factor participating in cell proliferation and DNA repair. Here, we explored the function of TaPCNA in wheat exposed to enhanced UV-B radiation by means of BSMV-VIGS. Results:The results showed the expression of TaPCNA was down-regulated by VIGS. Wheat leaves presented several spots after virus inoculation, and they were also found significantly curly and the whole plants were shorter than that of the control. The growth rate of wheat in each treatment was significantly inhibited after gene silencing (BSMV::TaPCNA). Especially, the growth of the gene silencing group was almost stagnant after processed with enhanced UV-B radiation (BSMV::TaPCNA+B). Also, the growth of uninoculated plants was suppressed after being exposed to enhanced UV-B radiation (WT+B). The cell length changed obviously, and the BSMV::TaPCNA group showed to be smaller cell than those of WT and BSMV:00 group. The physiochemical and metabolisms parameters were determined in different groups. The contents of soluble sugar and soluble protein decreased while the content of MDA increased in BSMV::TaPCNA group. In addition, the SOD activity enhanced while that of POD and CAT declined. These results indicated that the antioxidant system was destroyed after TaPCNA was silenced by VIGS. After exposed to enhanced UV-B radiation, the wheat growth in different group was less notable than TaPCNA silencing. Either in the BSMV:TaPCNA-1 or BSMV:TaPCNA-2 group. Both BSMV::TaPCNA group and BSMV::TaPCNA+B group demonstrated accumulation of small molecular weight DNA fragments and micronucleus through the DNA laddering and the PI staining. Conclusions: In summary, our results preliminarily illustrated the function of TaPCNA in apoptosis exposed to enhanced UV-B radiation and thus provided an idea for researchers to explore the function of certain genes in such a complex wheat genomes and offered theoretical basis to improve wheat agronomic trait.