Jasmonic acid contributes to rice resistance against Magnaporthe oryzae

Abstract

Background The annual yield losses caused by the Rice Blast Fungus, Magnaporthe oryzae, range to the equivalent for feeding 60 million people. To ward off infection by this fungus, rice has evolved a generic basal immunity (so called compatible interaction), which acts in concert with strain-specific defence (so-called incompatible interaction). The plant-defence hormone jasmonic acid (JA) promotes the resistance to M. oryzae, but the underlying mechanisms remain elusive. To get more insight into this open question, we employ the JA-deficient mutants, cpm2 and hebiba, and dissect the JA-dependent defence signalling in rice for both, compatible and incompatible interactions. Results We observe that both JA-deficient mutants are more susceptible to M. oryzae as compared to their wild-type background, which holds true for both types of interactions as verified by cytological staining. Secondly, we observe that transcripts for JA biosynthesis (OsAOS2 and OsOPR7), JA signalling (OsJAZ8, OsJAZ9, OsJAZ11 and OsJAZ13), JA-dependent phytoalexin synthesis (OsNOMT), and JA-regulated defence-related genes, such as OsBBTI2 and OsPR1a, accumulate after fungal infection in a pattern that correlates with the amplitude of resistance. Thirdly, induction of defence transcripts is weaker during compatible interaction. Conclusion The study demonstrates the pivotal role of JA in basal immunity of rice in the resistance to M. oryzae in both, compatible and incompatible interactions.

A tau class glutathione S‐transferase in tea plant, CsGSTU45, facilitates tea plant susceptibility to Colletotrichum camelliae infection mediated by jasmonate signaling pathway

“…In conclusion, the results from this study systematically showed that the JA signaling pathway modulates tea plant defenses against C. camelliae infection via the CsJAZ1/CsMYC2.2 module, thereby activating the downstream CsGSTU45 gene to promote the accumulation of H 2 O 2 (Figure 10). Besides, we found that JA signaling pathway plays a positive role in disease resistance against D. segeticola that causes leaf spot by increasing the content of H 2 O 2 (Figure S3), which conforms to the general opinion that JA signaling pathway positively regulates resistance against pathogens (Kazan & Manners, 2013;Ma et al, 2022;Shu et al, 2020;Wang et al, 2023). Besides, the expression level of CsGSTU45 in tea plant leaves inoculated with D. segeticola was significantly decreased after MeJA treatment at 24, 48, and 72 hpi (Figure S3d), indicating that the expression pattern of CsGSTU45 gene in the resistance against D. segeticola was different from that in the resistance against C. camelliae (Figure 4d).…”

Peruvian Amaranth (kiwicha) Accumulates Higher Levels of the Unsaturated Linoleic Acid

“…Compared to lipoxygenase and AOS, the pattern for allene oxide cyclase (AOC) does not contrast as clearly between A. hypochondriacus × hybridus and A. caudatus ( Figure 5 C). This is consistent with the published record, where the prolonged activation of the jasmonate pathway in response to abiotic [ 85 ] and biotic [ 86 ] stress factors was brought about by the induction of AOS as a key enzyme rather than by stimulation of its downstream partner AOC.…”

Endo‐1,4‐beta‐xylanase 1 (MoXYL1) secreted by Magnaporthe oryzae triggers defense responses and induces cell death in rice

“…Furthermore, within the hormone signaling‐related proteins, we identified JMT and four genes linked to JA biosynthesis, including LOX, AOS, and OPR. Several studies have demonstrated that both exogenous JA treatments and the overexpression of JA biosynthesis‐related genes enhance resistance against M. oryzae (Mei et al, 2006; Riemann et al, 2013; Ma et al, 2022). Additionally, a previous study highlighted that the activation of JMT expression leads to the production of methyl jasmonate, which serves as an intracellular regulator and a diffusible signal transducer in Arabidopsis (Seo et al, 2001).…”