Suwannarach Nakarin, Khuna Surapong, Thitla Tanapol, Senwanna Chanokned, Nuangmek Wipornpan, Kumla Jaturong, Lumyong Saisamorn
Office of Research Administration, Chiang Mai University, Chiang Mai, Thailand.
Center of Excellence in Microbial Diversity and Sustainable Utilization, Chiang Mai University, Chiang Mai, Thailand.
Front Plant Sci. 2024 Oct 10;15:1459759. doi: 10.3389/fpls.2024.1459759. eCollection 2024.
A significant global problem affecting muskmelon ( L.) is fruit rot caused by phytopathogenic fungi, which results in unsaleable products and substantial financial losses. In 2022 and 2023, fruit rot on muskmelon was found during the postharvest storage period in Phayao Province of northern Thailand. The aim of the current study was to isolate the species of fungi causing the fruit rot lesions. Out of the rot lesions on muskmelons, nine fungal isolates were received. All isolates of fungi were identified through a combination of morphological characteristics and molecular analyses. Based on their morphological traits, all isolated fungal isolate was assigned to the genus . All the fungal isolates were determined to belong to the species complex through multi-gene phylogenetic analysis employing the calmodulin (), RNA polymerase second largest subunit (), and translation elongation factor 1-alpha () genes. These isolates were identified as (SDBR-CMU483), (SDBR-CMU484, SDBR-CMU485, and SDBR-CMU486), (SDBR-CMU487 and SDBR-CMU488), and (SDBR-CMU489, SDBR-CMU490, and SDBR-CMU491). Moreover, pathogenicity tests were subsequently carried out, and the results indicated that all fungal isolates caused symptoms of fruit rot on inoculated muskmelon fruits. Notably, this result was consistent with the symptoms observed throughout the postharvest storage period. In the fungicide screening test, all fungal isolates showed sensitivity to copper oxychloride. However, all isolates showed insensitivity to benalaxyl-M + mancozeb, carbendazim, mancozeb, and metalaxy. To the best of our knowledge, the present study is the first to identify , , and as new causative agents of muskmelon fruit rot in Thailand and other regions globally. This is also the first report of postharvest fruit rot on muskmelons caused by in Thailand. Furthermore, the fungicide screening results indicate that fungicide resistance can be beneficial in developing potential management strategies against postharvest fruit rot disease of muskmelon caused by these four pathogenic species.
影响甜瓜（L.）的一个重大全球性问题是由植物病原真菌引起的果实腐烂，这会导致产品无法销售并造成重大经济损失。2022年和2023年，在泰国北部清莱府的采后储存期发现了甜瓜果实腐烂现象。本研究的目的是分离出导致果实腐烂病斑的真菌种类。从甜瓜的腐烂病斑中，获得了9株真菌分离株。所有真菌分离株均通过形态特征和分子分析相结合的方法进行鉴定。根据其形态特征将所有分离的真菌分离株归为某一属。通过使用钙调蛋白（）、RNA聚合酶第二大亚基（）和翻译延伸因子1-α（）基因进行多基因系统发育分析，确定所有真菌分离株均属于某一物种复合体。这些分离株被鉴定为（SDBR-CMU483）、（SDBR-CMU484、SDBR-CMU485和SDBR-CMU486）、（SDBR-CMU'487和SDBR-CMU488）以及（SDBR-CMU489、SDBR-CMU490和SDBR-CMU491）。此外，随后进行了致病性测试，结果表明所有真菌分离株对接种的甜瓜果实均造成了果实腐烂症状。值得注意的是，这一结果与采后储存期观察到的症状一致。在杀菌剂筛选试验中，所有真菌分离株对氧氯化铜表现出敏感性。然而，所有分离株对精甲霜灵+代森锰锌、多菌灵、代森锰锌和甲霜灵均表现出不敏感性。据我们所知，本研究首次将某几种菌鉴定为泰国及全球其他地区甜瓜果实腐烂的新致病因子。这也是泰国首次报道由某菌引起的甜瓜采后果实腐烂。此外，杀菌剂筛选结果表明，抗药性在制定针对由这四种致病真菌物种引起的甜瓜采后果实腐烂病的潜在管理策略方面可能有益。
