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Abstract In this study, we investigated the function of OsAAI1 in yield and drought tolerance by constructing overexpression line OE-OsAAI1 and mutant line osaai1. Bioinformatics analysis showed that the AAI gene-OsAAI1- belongs to the HPS_like subfamily of the AAI_LTSS superfamily, and OsAAI1 was localized in the nucleus. The expression of OsAAI1 was significantly induced by ABA and drought stress. OsAAI1 overexpression (OE19) significantly increased, and gene mutant (osaai1-1) repressed plant height, primary root length, lateral root number, grain size and yield in rice. Moreover, physiological and biochemical analyses showed that osaai1 was sensitive to drought stress, while OE19 enhanced the drought tolerance in rice. DAB and NBT staining revealed that under drought treatment, osaai1 accumulated a large amount of ROS compared with the wild type, while OE19 accumulated the least, and CAT, APX, GPX, GR activities were higher in OE19 and lower in osaai1, suggesting that OE19 improves rice tolerance to drought stress by enhancing ROS scavenging ability. OE19 also induce the expression of ABA-mediated regulatory pathway genes and enhance accumulation of ABA content in rice seedling. Predictably, OE19 displayed enhanced sensitivity to ABA, and ROS accumulation was significantly higher than in wild type and osaai1 under 3 µM ABA treatment. Thus, these results suggest that OsAAI1 is a positive regulator of rice yield and drought tolerance dependent on the ABA-mediated regulatory and ROS scavenging pathway.

To investigate the relationship between mineral elements and plum gummosis disease, Prunus salicina Lindl. trees with four grades of gummosis were used as the experimental materials. The contents of N, P, K, Ca, Mg, B, Fe, Mn, Zn and Cu in the branches and leaves were measured, and the correlation between mineral elements and gummosis was systemically analyzed through multiple comparisons, binary logistic regression analysis, and ordinal logistic regression analysis. In addition, the effects of prevention and control of the necessary mineral elements on the gummosis disease of P. salicina were verified after a fertilization experiment. The results indicate that the contents of nitrogen and manganese positively correlate with the occurrence of gummosis. In contrast, the contents of calcium and boron significantly negatively correlate with the occurrence of gummosis. A fertilization experiment facilitated the discovery that the control of nitrogen, as well as the increased application of boron and calcium fertilizers, contributed to the prevention and control on gummosis disease in P. salicina.