AUTHOR=Yang Yuxian , Xia Jiaxin , Fang Xiang , Jia Haoran , Wang Xicheng , Lin Yiling , Liu Siyu , Ge Mengqing , Pu Yunfeng , Fang Jinggui , Shangguan Lingfei 

TITLE=Drought stress in ‘Shine Muscat’ grapevine: Consequences and a novel mitigation strategy–5-aminolevulinic acid

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1129114

DOI=10.3389/fpls.2023.1129114

ISSN=1664-462X

ABSTRACT=<p>Drought is a common and serious abiotic stress in viticulture, and it is urgent to select effective measures to alleviate it. The new plant growth regulator 5-aminolevulinic acid <bold>(</bold>ALA<bold>)</bold> has been utilized to alleviate abiotic stresses in agriculture in recent years, which provided a novel idea to mitigate drought stress in viticulture. The leaves of ‘Shine Muscat’ grapevine (<italic>Vitis vinifera</italic> L.) seedlings were treated with drought (Dro), drought plus 5-aminolevulinic acid (ALA, 50 mg/L) (Dro_ALA) and normal watering (Control) to clarify the regulatory network used by ALA to alleviate drought stress in grapevine. Physiological indicators showed that ALA could effectively reduce the accumulation of malondialdehyde (MDA) and increase the activities of peroxidase (POD) and superoxide dismutase (SOD) in grapevine leaves under drought stress. At the end of treatment (day 16), the MDA content in Dro_ALA was reduced by 27.63% compared with that in Dro, while the activities of POD and SOD reached 2.97- and 5.09-fold of those in Dro, respectively. Furthermore, ALA reduces abscisic acid by upregulating <italic>CYP707A1</italic>, thus, relieving the closure of stomata under drought. The chlorophyll metabolic pathway and photosynthetic system are the major pathways affected by ALA to alleviate drought. Changes in the genes of chlorophyll synthesis, including <italic>CHLH</italic>, <italic>CHLD</italic>, <italic>POR</italic>, and <italic>DVR</italic>; genes related to degradation, such as <italic>CLH</italic>, <italic>SGR</italic>, <italic>PPH</italic> and <italic>PAO</italic>; the <italic>RCA</italic> gene that is related to Rubisco; and the genes <italic>AGT1</italic> and <italic>GDCSP</italic> related to photorespiration form the basis of these pathways. In addition, the antioxidant system and osmotic regulation play important roles that enable ALA to maintain cell homeostasis under drought. The reduction of glutathione, ascorbic acid and betaine after the application of ALA confirmed the alleviation of drought. In summary, this study revealed the mechanism of effects of drought stress on grapevine, and the alleviating effect of ALA, which provides a new concept to alleviate drought stress in grapevine and other plants.</p>