Characterization of SPL4's role in drought stress and trichome development in alfalfa
Abstract
The impacts of climate change are expected to increase the demand for crops that are resistant to drought stress. Understanding the molecular mechanisms involved in the response of plants to such stresses is thus crucial for preventing losses in crop yield. In this study, the role of alfalfa SPL4, a target of the non-coding RNA, miR156, was examined in response to drought stress and with respect to the development of trichomes. We found that transgenic alfalfa plants with RNAi-silenced SPL4 exhibited increased trichome density under both control and drought conditions. Furthermore, in response to withholding water for 14 days, SPL4-RNAi plants exhibited increased root length, water content, chlorophyll content, stomatal conductance, and increased water potential in leaves when compared to wild-type plants. RT-qPCR revealed that SPL4-RNAi plants displayed altered expression levels of genes involved in drought tolerance (SPL9, SPL13), antioxidant biosynthesis (CAT), and trichome production (GL1, GL3). This study demonstrates that SPL4 has a role in both trichome development and in the drought stress response, making it a potential target for the improvement of alfalfa and potentially other crops.