BZR1-NAC29-NAC31 signaling promotes the sheath blight resistance and tillering in rice

BZR1-NAC29-NAC31 signaling promotes the sheath blight resistance and tillering in rice

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Abstract Improving disease resistance is a primary objective in crop breeding.However, the signaling mechanisms governing disease resistance and yield are frequently controlled antagonistically, posing challenges in balancing crop productivity and disease resistance.Prior research has shown that Brassinazole resistant 1 bostik universal primer pro (BZR1) enhances resistance to rice sheath blight (ShB) and increases tillering in rice.Here, we found that BZR1 interacts with NAC29 and NAC31, the primary transcription factors responsible for regulating the formation of the secondary cell wall.

The interaction between NAC29 and NAC31 was demonstrated by yeast two-hybrid and bimolecular fluorescence complementation tests.The expression of NAC29 and NAC31 increased significantly in response to Rhizoctonia solani infection.The susceptibility of the nac29nac31 double mutant to ShB was increased, but the overexpression of NAC29 and NAC31 reduced susceptibility to ShB compared with the single mutants or wild-type plants.Like the bzr1-D, a BZR1 dominant negative mutant, NAC29 and NAC31 overexpressors increased tiller numbers.

Co-expression of BZR1 and NAC29 or NAC31 enhanced cinnamyl alcohol dehydrogenase 8B (CAD8B) expression while inhibiting teosinte branched 1 (TB1) expression to a greater extent than the expression of BZR1 alone.Furthermore, the expression level of CAD8B was elevated in NAC29-OX and NAC31-OX plants, but the expression level of TB1 was reduced in NAC29-OX and NAC31-OX plants compared to the wild-type plants.The results showed that BZR1-NAC29-NAC31 improves rice resistance swish supreme glide track white and tillering by controlling the expression of CAD8B and TB1, respectively.These findings offer valuable targets for breeding that can avoid the trade-off between growth and defense.