Differences of physiological responses and transcriptional regulation of alfalfa with different drought tolerances under drought stresses
Year: 2023
Type: article
Abstract: Alfalfa is the most important legume forage, which is often planted in aird or semi-arid regions. The objective of this study is to explore the responsive mechanism of alfalfa with different drought tolerance to drought stress, which provides the theoretical basis for tolerant breeding of alfalfa. In this study, the new variety Medicago sativa ‘Zhongke 1’ was used as the test material, and M. sativa ‘Sanditi’ was used as the control. The effects of drought stress on growth traits, photosynthesis, chlorophyll concentration, leaf water content, osmotic adjustment substances, and antioxidant enzyme activities were determined by natural drought strategy in pots. The deferentially expressed genes were compared by transcriptome analysis. Drought stress significantly reduced plant height, biomass, relative water content of leaves, photosynthetic rate, transpiration rate, stomatal conductance, intercellular carbon dioxide and chlorophyll concentration of alfalfa. Compared with Sanditi, Zhongke 1 revealed the lower malondialdehyde concentration and electrical conductivity under drought stress, but stronger osmotic regulation ability and superoxide radical scavenging ability. Transcriptome sequencing identified 5308 and 8053 drought-responsive genes of Zhongke 1 and Sanditi, respectively. GO functional annotation demonstrated that 346 drought-responsive genes were significantly enriched in six GO item categories in Zhongke 1, while 1683 drought-responsive genes in Sanditi were significantly enriched in 29 GO item categories. The relative expression levels of 19 key drought-tolerant genes in Zhongke 1 were significantly higher than those in Sanditi. Alfalfa may maintain a relatively high photosynthetic rate by up-regulating the relative expression levels of drought tolerant genes SUS, P5CS, LEA, SOD, POD, PEPC, and NCED, thus improving osmotic regulation ability and antioxidant enzyme activity. The results provide a theoretical basis for further exploration of alfalfa’s candidate genes in response to drought stress and drought tolerant breeding.
Source: ACTA AGRONOMICA SINICA
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $941
OpenAlex ID: W4408945253