Glucose-6-phosphate dehydrogenase plays a vital role in Achnatherum inebrians plants host to Epichloe gansuensis by improving growth under nitrogen deficiency

Low nitrogen negatively affects soil fertility and plant productivity. Glucose-6-phosphate dehydrogenase (G6PDH) and EpichloA << gansuensis endophytes are two factors that are associated with tolerance of Achnatherum inebrians to abiotic stress. However, the possibility that E. gansuensis interacts with G6PDH in enhancing low nitrogen tolerance of host grasses has not been examined. A. inebrians plants with (E+) and without E. gansuensis (E-) were subjected to different nitrogen concentration treatments (0.1, 1, and 7.5 mM). After 90 days, physiological studies were carried out to investigate the participation of G6PDH in the adaption of host plants to low nitrogen availability. Low nitrogen retarded the growth of A. inebrians. E+ plants had higher total dry weight, chlorophyll a and b contents, net photosynthesis rate, G6PDH activity, and GSH content, while having lower plasma membrane (PM) NADPH oxidase activity, NADPH/NADP(+) ratios, and MDA and H2O2 than in E- A. inebrians plants under low nitrogen concentration. The presence of E. gansuensis played a key role in maintaining the growth of the A. inebrians plants under low nitrogen concentration by regulating G6PDH activity and the NADPH/NADP(+) ratio and improving net photosynthesis rate.