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Melon is one of the most important horticultural crops in Asia. Powdery mildew (PM) is frequently occurred in facility cultivation, which seriously affects its yield and fruit quality of melon. Light signal is the basis of plant growth and development, and appropriate red light (RL) plays an important role in regulating the resistance of plant pathogens. Reactive oxygen species (ROS) also have been shown to be participated in plant defence against pathogen infection. However, whether light is involved in PM resistance through ROS remains unclear. Here, we found that RL+PM treatment significantly enhanced the resistance of PM in melon seedlings, improved NADPH oxidase activity, upregulated respiratory burst oxidase homologue 1 (RBOHD) expression, and increased hydrogen peroxide (H 2 O 2) level. Compared with the PM treatment alone, diphenylene iodonium (DPI)+PM treatment significantly enhanced the sensitivity to PM in melon seedlings and weakened the effect of RL-induced PM resistance. Further studies showed that silencing CmRBOHD significantly inhibited the RL-induced PM resistance by inhibiting H 2 O 2 synthesis. In addition, CmWRKY50 could activate CmRBOHD expression by binding to the promoter of CmRBOHD. Taken together, the results suggest that RL can increase endogenous H 2 O 2 levels and induce the initiation of defence through activation of CmWRKY50 , and therefore, when plants are subjected to pathogen stress, higher H 2 O 2 levels in the plants are beneficial for organizing the invasion of pathogens and enhancing powdery mildew resistance. • Red light pretreatment significantly improved powdery mildew resistance in melon seedlings. • Red light pretreatment significantly increased the activity of NADPH oxidase and promoted H 2 O 2. • CmWRKY50 activated the expression of CmRBOHD by binding to the CmRBOHD promoter. [ABSTRACT FROM AUTHOR]

Mungbean (Vigna radiata L.), one of the most widely grown edible legumes in Asia, plays important roles in the improvement of agricultural cultivation systems as well as human diets. As an understudied crop, however, most mungbean varieties are characterized by unstable yields, poor disease resistance, and unsuitability for mechanical harvesting, thereby leading to a low production income. We, therefore, developed Jilv 20, a new mungbean cultivar with a dull seed coat, by crossing Bao 942-34 with Weilv 9002-341. After 11 years of selection and evaluation, Jilv 20 has shown wide adaptability, early maturity, high yield, halo blight resistance, and suitability for mechanical harvesting. The growth period of Jilv 20 is 79.5 and 66.7 days in the spring and summer sowing seasons, respectively, and the average plant height is approximately 56.4 cm. In this study, average yields were 1737.9, 1532.3, and 2045.1 kg/hm2 in northern spring-sowing, northern summer-sowing, and southern sites, respectively; these values were respectively 27.83%, 28.48%, and 6.96% higher than those of control cultivar Zhonglv 5, which has been popular in past decades because of its wide adaptability. The average protein and starch contents of Jilv 20 seeds were 25.0% and 49.56%, respectively. Further application and extension of Jilv 20 in China should contribute to mungbean production, breeding, and industrial development. [ABSTRACT FROM AUTHOR]