UC Riverside

Huanglongbing (HLB) is a significant global concern for citrus orchards. However, certain “Survivor Trees” have demonstrated tolerance and recovery from the disease, presenting potential avenues for HLB cures and prevention. This study delves into the mechanisms behind this resilience. My findings indicate that the Survivor Tree Phenotype might be primarily influenced by host-microbe interactions. Additionally, microbial dynamics reveal that certain microbes might exacerbate or mitigate HLB effects. Another key insight is the potential role of callose, a polysaccharide associated with defense mechanisms, which may interact with the putative pathogen 'Candidatus Liberibacter asiaticus' (CLas) and the enzyme β-1,3-glucanase from Streptomyces spp. to influence the Survivor Tree Phenotype. Transcriptomic analyses further highlight unique gene expression patterns related to disease resistance and callose synthesis. In sum, this study offers insights into HLB resilience, suggesting areas for further exploration, particularly around the interactions of callose, CLas, and Streptomyces, to enhance our understanding of HLB tolerance mechanisms.