1. Moleuclar mechanism of plant peptide signals transducted by receptor-like kinases

Plant receptor-like kinases (RLKs) possess large amounts of members in genomes of different species, which play the major roles in plant-environment interactions and intercellular communications. Plant peptide signals are widely known to be perceived by RLKs and regulate plant growth, development, reproduction, immunity and so forth. The group leader has achieved progress in the moleuclar mechanism of an RLK protein, PSKR, transducting its peptide signal, PSK, by elucidating five crystal structures of PSKR protein or signaling complexes in three different states (Wang et al., Nature 2015). In this research progress, the first structure of minimal unit of signaling complex constituted of plant peptide signal and its RLK receptor was revealed; another RLK, SERK, acting as the coreceptor of PSKR was also identified and was further believed to be the common coreceptor of other LRR-RLKs to perceive peptide signals. From the perspective of structural biology, the allosteric activation mechanism of PSKR differs to the “molecular glue” activation mechanism adopted by the well-studied RLK, such as BRI1 and FLS2. Based on these molecular structures, the analogues of PSK, which are suitable for plant growth additives, can be designed for crops yield promotion.

2. Structural and functional study of plant resistance protein and resistosome

Plants and animals have hit upon similar immune strategies to protect themselves against pathogens. One important mechanism is defined by cytoplasmic immune receptors called NLRs that, in plants, recognize so-called effectors, molecules that invading microorganisms secrete into the plant’s cells. Host recognition of effectors by NLRs, whether direct or indirect, results in cell death and immune responses to confine microbes to the site of infection. However, until now, a detailed understanding of the mechanisms of action of plant NLRs has been lacking. In the group leader’s recent two new studies, they focused their attentions on a plant NLR called ZAR1 and pieced together the sequence of molecular events that convert inactive NLR molecules into active complexes, which they termed ‘resistosome’ that provide disease resistance. One striking feature of plant resistosome is its similarity with animal NLR proteins, which, once activated, also assemble into wheel-like structures called ‘inflammasomes’ that act as signaling platforms for cell death execution and immune signaling. However, one important difference between the structures offers a tantalizing clue as to how ZAR1 induces cell death. Thus, these findings have important general implications for understanding plant immunity (Wang et al., Science 2019a and 2019b). These progresses are well commented in Science, Nature Plants, Trends in Immunology and so forth, and praised as landmark studies and textbook knowledge in plant immunity.

Qiujiao Yang, Jing Li, Zhengdong Wang, Yuxuan Zhang, Ruihan Wang, Xiaoxue Chen, Yanping Song, Meng Wang, Cheng Chi, Xuehui Li, Wenfeng Wang, Didi Zhao