trease-cox1-sequences-MSA-output-Saprolegnia-spp.

<i>Saprolegnia</i>, a notable genus within the <i>Saprolegniales</i>, is known for its pathogenic tendencies on a wide range of aquatic organisms, causing infections such as saprolegniasis and Epizootic Ulcerative Syndrome (EUS). From late 1985 to early 1986, accounts of local periodic EUS outbreaks were reported. However, the infection has primarily been associated with <i>Aphanomyces</i> sp., another genus within the same order, rather than <i>Saprolegnia</i> sp. The only species from this genus documented in the country thus far is <i>Saprolegnia diclina</i>, with the last recorded isolation occurring sixty years ago. No member of the genus has been isolated, much less rediscovered, since then. It is speculated that its rarity is due to elevated temperatures in the Philippines, which created unfavorable conditions for its growth. Considering this, the study deliberately targeted a remote highland area with low temperatures, specifically in Kibungan, Benguet, Philippines, in search of cold-dwelling <i>Saprolegnia</i> species in the tropics. Two isolates, collected from muddy water samples baited using sesame seeds, underwent morphological, physiological, and molecular analyses and were identified as <i>Saprolegnia ferax</i>. Further, the findings emphasize the importance of temperature as a key growth and dispersal factor as the isolates thrive within the range of 15 ºC to 30 ºC yet exhibit limited growth at temperatures equal to or beyond 35ºC. This paper describes the second <i>Saprolegnia </i>report for the Philippines.

水霉属（Saprolegnia）是水霉目（Saprolegniales）下的重要类群，可侵染多种水生生物并引发致病感染，如水霉病与流行性溃疡综合征（Epizootic Ulcerative Syndrome, EUS）。1985年末至1986年初，当地曾有周期性EUS暴发的报道，但此类感染主要被认为与同目下的丝囊霉属（Aphanomyces）物种相关，而非水霉属（Saprolegnia）物种。截至目前，该国仅记录过双游水霉（Saprolegnia diclina）这一种水霉属物种，最后一次分离记录距今已有60年，此后再未分离到该属的任何成员，更遑论重新发现。有研究推测，菲律宾地区的高温环境不利于该属物种生长，导致其极为罕见。鉴于此，本研究特意选取菲律宾本格特省基邦根（Kibungan, Benguet）这一低温偏远高地，旨在搜寻热带地区的嗜冷水霉属物种。研究人员以芝麻籽为诱饵采集泥水样本，获得两株分离菌株，通过形态学、生理学及分子生物学分析，将其鉴定为大孢水霉（Saprolegnia ferax）。此外，研究结果进一步明确了温度作为关键生长与传播因子的重要性：两株菌株在15℃至30℃范围内均可良好生长，但在35℃及以上温度下生长受限。本文为菲律宾地区第二篇关于水霉属的研究报道。