Phytophthora Species from Xinjiang Wild Apple Forests in China

Abstract

Phytophthora species are well-known destructive forest pathogens, especially in natural ecosystems. The wild apple (Malus sieversii (Ledeb.) Roem.) is the primary ancestor of M. domestica (Borkh.) and important germplasm resource for apple breeding and improvement. During the period from 2016 to 2018, a survey of Phytophthora diversity was performed at four wild apple forest plots (Xin Yuan (XY), Ba Lian (BL), Ku Erdening (KE), and Jin Qikesai (JQ)) on the northern slopes of Tianshan Mountain in Xinjiang, China. Phytophthora species were isolated from baiting leaves from stream, canopy drip, and soil samples and were identified based on morphological observations and the rDNA internal transcribed spacer (ITS) sequence analysis. This is the first comprehensive study from Xinjiang to examine the Phytophthora communities in wild apple forests The 621 resulting Phytophthora isolates were found to reside in 10 different Phytophthora species: eight known species (P. lacustris being the most frequent, followed by P. gonapodyides, P. plurivora, P. gregata, P. chlamydospora, P. inundata, P. virginiana, and P. cactorum) and two previously unrecognized species (P. sp. CYP74 and P. sp. forestsoil-like). The highest species richness of Phytophthora occurred at BL, followed by XY. P. lacustris was the dominant species at BL, XY, and JQ, while P. gonapodyides was the most common at KE. In the present paper, the possible reasons for their distribution, associated implications, and associated diseases are discussed.

Phytophthora, Nothophytophthora and Halophytophthora diversity in rivers, streams and riparian alder ecosystems of Central Europe

“…The high prevalence of P. gonapodyides and P. lacustris in watercourses of Central Europe is in accordance with previous surveys performed in the Mediterranean (Jung et al 2019 ; Seddaiu et al 2020 ; Riolo et al 2020 ) and Northern Europe (Redondo et al 2018a ). Both species are considered native to Europe and widespread on several continents (Greslebin et al 2005 ; Reeser et al 2011 ; Huai et al 2013 ; Nagel et al 2013 ; Shrestha et al 2013 ; Stamler et al 2016 ; Jung et al 2018b ; Xu et al 2019 ). Phytophthora lacustris is predominantly an aquatic saprotroph on plant debris but can also act as opportunistic pathogen of riparian trees and irrigated trees and crops (Orlikowski et al 2011 ; Nechwatal et al 2013 ; Jung et al 2016 ; Kanoun-Boulé et al 2016 ).…”

“…Phytophthora chlamydospora, another clade 6 species, was exclusively detected in three Austrian watercourses. Considered as native in North America, P. chlamydospora has been found widespread in all continents except Antarctica (Greslebin et al 2005;Jung 2009;Reeser et al 2011;Huai et al 2013;Oh et al 2013;Hansen et al 2015;Sims et al 2015;Jung et al 2016Jung et al , 2017aJung et al , 2018bJung et al , 2019Jung et al , 2020Bily et al 2018Bily et al , 2022Xu et al 2019;Corcobado et al 2020;. Although P. chlamydospora has a predominantly waterborne saprophytic lifestyle (Brasier et al 2003;Hansen et al 2015;Sims et al 2015;Bily et al 2018Bily et al , 2022, it can act as an opportunistic tree pathogen in natural ecosystems (Bily et al 2022) and as aggressive pathogen in orchards and nurseries (Derviş et al 2016;Jung et al 2016;Browne et al 2020Browne et al , 2021.…”

Extensive morphological and behavioural diversity among fourteen new and seven described species in Phytophthora Clade 10 and its evolutionary implications

“…In China, P. taxon gallica-like 3 was recently found in the cold-temperate north eastern region, whereas in the temperate far western Tian Shan mountains in Xinjiang and in the mountains of Yunnan in the south west no Clade 10 species were recovered ( Huai et al 2013 , Xu et al 2019 ). Other regions apparently also devoid of Clade 10 species are: the temperate regions of eastern Australia ( Burgess et al 2017 , Kaliq et al 2019 ); the Mediterranean regions of Europe ( Vettraino et al 2002, 2005 , Balci & Halmschlager 2003 , Català et al 2015 , Scanu et al 2015 , Jung et al 2019 , Seddaiu et al 2020 ); the southwestern USA ( Hansen et al 2012a , Stamler et al 2016 , Frankel et al 2020 ); Western Australia ( Hüberli et al 2013 , Burgess et al 2017 ) with the exception of sporadic isolation of P. gondwanensis ( Burgess et al 2021 ); and the tropical and subtropical lowland rainforests and monsoon forests in Taiwan ( Jung et al 2017a ), Vietnam ( Jung et al 2020 ), Hainan ( Zeng et al 2009 ), Borneo and Sumatra (T. Jung, A. Durán & M. Junaid, unpublished results), Guyana ( Legeay et al 2020 ) and Central America and Peru (T. Jung, Y. Balci & K. Broders, unpublished results).…”