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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Molecular Plant Pathology Laboratory » Research » Publications at this Location » Publication #413566
Research Project: Omics-Based Approach to Detection, Identification, and Systematics of Plant Pathogenic Phytoplasmas and Spiroplasmas

Location: Molecular Plant Pathology Laboratory

Title: Momordica charantia is a novel host of 'Candidatus Phytoplasma malaysianum'-related strains associated with bitter melon stem fasciation disease in China

Author
item Bottner, Kristi
item QIAO, KAI - Yunnan Agricultural University
item HUANG, WEIYI - Yunnan Agricultural University
item Zhao, Yan
item YANG, ZIXIANG - Yunnan Academy Of Agriculture Sciences
item CAI, HONG - Yunnan Agricultural University
item Wei, Wei

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2024
Publication Date: 6/11/2024
Citation: Bottner-Parker, K.D., Qiao, K., Huang, W., Zhao, Y., Yang, Z., Cai, H., Wei, W. 2024. Momordica charantia is a novel host of 'Candidatus Phytoplasma malaysianum'-related strains associated with bitter melon stem fasciation disease in China. Plant Disease. https://doi.org/10.1094/PDIS-05-24-0971-PDN.
DOI: https://doi.org/10.1094/PDIS-05-24-0971-PDN

Interpretive Summary: Bitter melon, native to tropical and subtropical regions, is valued for its edible fruit and medicinal properties. Since 2022, symptomatic bitter melons have been observed in Wenshan, Yunnan Province, China. The affected plants exhibited stem fasciation and excessive tendril growth, which ARS scientists in Beltsville, Maryland suspected were caused by phytoplasma infection. In collaboration with Chinese scientists, ARS scientists conducted molecular diagnostic analysis by using three genetic markers unique to phytoplasma. The phytoplasmas responsible for the observed stem fasciation were identified as belonging to the 16SrXXXII-subgroup, marking the first documented instance of such strains in bitter melon in China. These findings will benefit researchers and students engaged in phytoplasma detection, identification, and understanding genetic diversity. In addition, the results have important implications for extension personnel and farmers in developing disease management strategies.

Technical Abstract: In 2022, unusual symptoms were observed on bitter melon plants in Wenshan, Yunnan Province, China, characterized by stem fasciation and excessive tendril growth. Given the region's history of phytoplasma diseases, including those affecting other plant species like happy tree (Amptotheca accuminata) and Trema tomentosa, phytoplasma was suspected to be associated with this new bitter melon disease. To confirm phytoplasma infection, symptomatic bitter melon samples underwent nested PCR analysis targeting the 16S rDNA gene, revealing positive results in three out of four tested plants. Subsequent iPhyClassifier analysis identified the phytoplasma strains associated with bitter melon stem fasciation (BMSF) disease as belonging to 16SrXXXII-D subgroup, and the representative strain was designated as BMSF1. To further characterize the BMSF1 strain, rp and secY genes were also amplified and sequenced. The sequence analysis shows significant similarity to 'Candidatus Phytoplasma luffae' because comparisons within the 16SrXXXII-D subgroup were limited due to the availability of sequences. While strains within the 16SrXXXII-D subgroup had been reported in ornamental plants, this discovery marks the first documented case of BMSF disease in bitter melon in China, expanding the known host range of 'Ca. Phytoplasma malaysianum'-related strains. These findings highlight the importance of monitoring and management strategies for phytoplasma diseases in bitter melon cultivation to minimize economic losses and protect crop health.