TaPCNA plays a role in programmed cell death after UV-B exposure in wheat (Triticum aestivum)

Abstract

Ultraviolet (UV)-B is a component of sunlight and shows a significant effect on DNA damage, which can be regulated by proliferating cell nuclear antigen (PCNA). The role of TaPCNA in wheat (Triticum aestivum L.) programmed cell death (PCD) under UV-B has not been investigated previously. Here, we explored the function of TaPCNA in wheat exposed to UV-B utilising Barley Stripe Mosaic Virus–virus-induced gene silencing (VIGS). The results showed that the expression of TaPCNA was downregulated, and curly wheat leaves with several spots were determined by VIGS. The growth rate and mesophyll cell length were significantly inhibited after TaPCNA was silenced. The activity of superoxide dismutase and the contents of soluble sugar and soluble protein decreased, whereas the activities of peroxidase and catalase and malondialdehyde content increased in TaPCNA-silenced and UV-B treatment groups. DNA laddering and propidium iodide staining results showed that DNA fragments and micronucleus accumulated after TaPCNA silencing with or without UV-B. Thus, TaPCNA participates in plant growth and DNA damage and PCD under UV-B. This study suggests an idea for the exploration of the function of certain genes in such complex wheat genomes and offers a theoretical basis to improve wheat agronomic traits.