Enhancing rice crop resistance against brown plant hopper infestation through the foliar application of sodium nitroprusside

Abstract Plant hoppers are pest herbivores that significantly affect the growth and productivity of rice worldwide. This study aimed to investigate the role of two chemicals, sodium nitroprusside (SNP), a nitric oxide inducer, and carboxy-PTIO potassium salt, a nitric oxide scavenger, under brown plant hopper (BPH) stress in rice. Screening tests were performed to evaluate various factors, including agronomic traits, relative water content, electrolytic leakage, gene expression, and nitric oxide (NO) production. Interestingly, the positive control and 100 µM cPTIO-treated seedlings showed decreased root and shoot growth, reduced relative water content, and induced electrolytic leakage under BPH stress. Similarly, the positive control and 100 µM cPTIO-treated seedlings exhibited decreased survival percentage and increased death rate under BPH stress. Gene expression analysis revealed that after 6, 12, and 24 h of BPH stress, the levels of OsNOA1 and OsEF-1α were significantly higher in the resistant rice lines Cheongcheong and Nagdong Double haploid (CNDH)-78 and CNDH-87, while OsNOA1 and OsNR were upregulated in the the susceptible rice lines CNDH 14 − 2 and CNDH 48 − 3. Moreover, the resistant lines exhibited increased NO content after 6, 12, and 24 h, and susceptible rice lines showed high NO content after 24 h of BPH stress. These findings suggest that the application of 100 µM SNP enhanced internal NO production and content, improved the overall agronomic traits, increased the relative water content, decreased electrolytic leakage, and protected rice from the harmful effects of BPHs.