Plant Biotechnology Journal最新文献

Tomato is one of the most economically important vegetable crops in the world and has been seriously affected by the devastating agricultural pest root-knot nematodes (RKNs). Current understanding of tomato resistance to RKNs is quite limited. VQ motif-containing family proteins are plant-specific regulators; however, whether and how tomato VQs regulate resistance to RKNs is unknown. Here, we found that SlVQ15 recruited SlWRKY30IIc to coordinately control tomato defence against the RKN Meloidogyne incognita without affecting plant growth and productivity. The jasmonate (JA)-ZIM domain (JAZ) repressors of the phytohormone JAs signalling associated and interfered with the interaction of SlVQ15 and SlWRKY30IIc. In turn, SlWRKY30IIc bound to SlJAZs promoters and cooperated with SlVQ15 to repress their expression, whereas this inhibitory effect was antagonized by SlJAZ5, forming a feedback regulatory mechanism. Moreover, SlWRKY30IIc expression was directly regulated by SlMYC2, a SlJAZ-interacting negative regulator of resistance to RKNs. In conclusion, our findings revealed that a regulatory circuit of SlVQ15-SlWRKY30IIc and the JA pathway fine-tunes tomato defence against the RKN M. incognita, and provided candidate genes and clues with great potential for crop improvement.

It is urgent to mine novel blast-resistant genes in rice and develop new rice varieties with pyramiding blast-resistant genes. In this study, a new blast-resistant gene, OsBRW1, was screened from a set of rice near-isogenic lines (NILs) with different blast-resistant ability. Under the infection of Magnaporthe oryzae (M. oryzae), OsBRW1 in the resistant NIL Pi-4b was highly induced than that in the susceptible NIL Pi-1 and their parent line CO39, and the blast-resistant ability of OsBRW1 was further confirmed by using CRISPR/Cas9 knockout and over-expression methods. The protein encoded by OsBRW1 was a typical NBS-LRR with NB-ARC domain and localized in both cytoplasm and nucleus, and the transient expression of OsBRW1 was capable of triggering hypersensitive response in tobacco leaves. Protein interaction experiments showed that OsBRW1 protein directly interacted with OsSRFP1. At the early infection stage of M. oryzae, OsBRW1 gene induced OsSRFP1 to highly expression level and accumulated H₂O₂, up-regulated the defence responsive signalling transduction genes and the pathogenesis-related genes and increased JA and SA content in the resistant NIL Pi-4b. By contrary, lower content of endogenous JA and SA in osbrw1 mutants was found at the same stage. After that, OsSRFP1 was down-regulated to constitution abundance to balance the growth of the resistant NIL Pi-4b. In summary, OsBRW1 solicited OsSRFP1 to resist the infection of blast fungus in rice by inducing the synergism of induced systemic resistance (ISR) and system acquired resistance (SAR) and to balance the growth of rice plants.

Heat stress (HS) has become a major factor limiting crop yields worldwide. HS inhibits plant growth by ROS accumulation, and NADPH oxidases (Rbohs) are major ROS producers in plants. Here, we show that CRISPR/Cas knockout of the OsRbohB (OsRbohB-KO) significantly increased rice tolerance to HS imposed at various different growth stages. We produced OsRbohB-KO and OsRbohB-overexpression (OsRbohB-OE) lines in a japonica cultivar, Nipponbare. Compared with nontransgenic wild-type (WT) plants, the OsRbohB-KO lines showed a significant increase in chlorophyll contents (5.2%-58.0%), plant growth (48.2%-65.6%) and grain yield (8.9%-20.5%), while reducing HS-induced ROS accumulation in seeds (21.3%-33.0%), seedlings (13.0%-30.4%), anthers (13.1%-20.3%) and grains (9.7%-22.1%), under HS conditions. Analysis of yield components revealed that the increased yield of OsRbohB-KO plants was due to increased starch synthetase activity, spikelets per panicle (2.0%-9.3%), filled spikelets (4.8%-15.5%), percentage of filled spikelets (2.4%-6.8%) and 1000-grain weight (2.9%-7.4%) under HS conditions during the reproductive stage. Grain milling and appearance quality, and starch content were also significantly increased in OsRbohB-KO plants under HS conditions during the mature stage. Furthermore, OsRbohB-KO significantly upregulated the expression levels of heat shock-related genes, OsHSP23.7, OsHSP17.7, OsHSF7 and OsHsfA2a, in rice seedlings and grains under long-term HS conditions. Conversely, OsRbohB-OE resulted in phenotypes that were opposite to OsRbohB-KO in most cases. Our results suggest that suppression of OsRbohB provides an effective approach for alleviating heat damage and improving grain yield and quality of rice under long-term HS conditions.