Ze Sun, Jin-Hua Shi, Tao Fan, Chao Wang, Le Liu, Huanan Jin, Caroline Ngichop Foba, Man-Qun Wang.

Pest Manag Sci. 2020 Nov; 76(11):3649-3656. doi: 10.1002/ps.5911. Epub 2020 Jun 5.

Abstract

Background: Brown rice planthopper (BPH) is a devastating rice pest in Asia. Bph14 is the first cloned BPH-resistance gene in rice, inducing callose deposition while impeding BPH feeding. Nitrogen application affects plant growth and resistance. However, there is little evidence on the influence of nitrogen on the callose content or regulation of rice BPH resistance. In this study, Luoyou9348 (containing Bph14 and highly resistant to BPH) and Yangliangyou6 (without Bph14 and susceptible to BPH) were planted under varying nitrogen regimes (0 , 90, 180 kg ha^-1 ) to determine their effects on the resistance levels of rice to BPH feeding. The experiments involved BPH performance, plant volatile profiling and BPH preferences in laboratory and field experiments.

Results: We found that BPH egg hatching rate, total number of eggs laid and BPH preference increased with increasing nitrogen application in both rice varieties. However, the expression of Bph14, callose content and BPH feeding significantly declined with an increase in nitrogen fertilization in Luoyou9348, compared with Yangliangyou6. Also, the emission of volatile terpene compounds increased with increasing nitrogen application, which resulted in an increase in BPH numbers on both varieties. Two-way analysis of variance indicated a significant interaction between rice variety and nitrogen in BPH feeding behavior.

Conclusion: Our findings provide an insight for addressing problems involved in the incorporation of insecticidal genes into crop plants. The effects of nitrogen on insecticidal gene expression in rice plant defense are discussed. © 2020 Society of Chemical Industry.

See https://pubmed.ncbi.nlm.nih.gov/32418333/

Figure 2: BPH oviposition and development from newly hatched egg to adult in different nitrogen‐treated rice plants. (a) Mean duration of BPH nymphs to adult (± SE, n = 6). (b) Mean hatch rate of BPH eggs from adults reared on different nitrogen‐treated plants (± SE, n = 6). (c) Mean number of BPH eggs laid on rice plants (± SE, n = 6). HN, high nitrogen treatment; GSRN, Green Super Rice nitrogen treatment; 0N, no nitrogen treatment; LY9348, Luoyou9348 rice variety; YLY6, Yangliangyou6 rice variety. Different letters above bars in the same group are significantly different (P < 0.05). Asterisks indicate a significant difference between LY9348 and YLY6 at **P < 0.01 and ***P < 0.001.