Find in Library

Lesion mimic mutants (LMMs) are ideal materials for studying cell death and resistance mechanisms. Here, we identified and mapped a novel rice LMM, <i>g380</i>. The <i>g380</i> exhibits a spontaneous hypersensitive response-like cell death phenotype accompanied by excessive accumulation of reactive oxygen species (ROS) and upregulated expression of pathogenesis-related genes, as well as enhanced resistance to <i>Xanthomonas oryzae</i> pv. <i>oryzae</i> (<i>Xoo</i>). Using a map-based cloning strategy, a 184,916 bp deletion on chromosome 2 that overlaps with the diterpenoid biosynthetic gene cluster was identified in <i>g380</i>. Accordingly, the content of diterpenoids decreased in <i>g380</i>. In addition, lignin, one of the physical lines of plant defense, was increased in <i>g380</i>. RNA-seq analysis showed 590 significantly differentially expressed genes (DEG) between the wild-type <i>9311</i> and <i>g380</i>, 585 of which were upregulated in <i>g380</i>. Upregulated genes in <i>g380</i> were mainly enriched in the monolignol biosynthesis branches of the phenylpropanoid biosynthesis pathway, the plant–pathogen interaction pathway and the phytoalexin-specialized diterpenoid biosynthesis pathway. Taken together, our results indicate that the diterpenoid biosynthetic gene cluster on chromosome 2 is involved in immune reprogramming, which in turn regulates cell death in rice.