Genetic breeding and biocontrol strategies for managing bacterial leaf streak in rice: A comprehensive review

Abstract

Xanthomonas oryzae pv. oryzicola (Xoc), a key bacterial pathogen of rice, causes bacterial leaf streak (BLS)-a destructive and quarantinable disease that often leads to significant yield and quality losses and poses serious challenges to rice production. Developing effective green control strategies for BLS represents a critical challenge that must be addressed in current rice production systems. Although the use of disease-resistant genes for genetic breeding appears to be an efficient and durable strategy for controlling BLS, progress in this area has been slow due to the limited availability of major resistance (R) gene resources effective against BLS to date. To provide a comprehensive understanding of how disease-resistant genes can be utilized against BLS, this review systematically compiles and analyzes the functions of key genetic resources in rice BLS resistance. These include: (1) R genes such as Rxo1, bls1/2, and Xo1/2; (2) Quantitative trait loci (QTLs) like qBlsr5a, qBLSR-11–1, qBLS6.2 and so on; (3) Multiple defense-related (DR) genes. Furthermore, this article also collected biocontrol agents (BCAs) against BLS, summarizing researches on inhibition of Xoc through microorganisms and their antagonistic metabolites, and plant-derived compounds. Based on this, we proposed strategies that include engineering chimeric of Bs2-NRC2/3/4 or promoters of Xa27 and Xa23 to enable recognition of conserved Xoc effectors, and perform gene editing effector-binding elements (EBEs) in the promoters of OsSULTR3;6, OsHXK5, OsF3H03g, etc. to prevent induction. We also proposed a novel biological control strategy against BLS, which employs different functional BCAs and genetically modifies Microbiome (M) genes to recruit beneficial microorganisms.