Population structures of the water-borne plant pathogen Phytopythium helicoides reveal its possible origins and transmission modes in Japan

Abstract

The purpose of this study was to clarify the genetic diversity of Phytopythium helicoides and to understand the transmission mode of the pathogen in Japan. In total, 232 P. helicoides isolates were collected from various host plants and geographic origins, including farms and natural environments. We developed 6 novel microsatellite markers for use in the study and found 90 alleles among the 6 markers in the 232 isolates. The analysis of molecular variance suggested that P. helicoides has high variance within individuals and low fixation indices between populations. A phylogenetic analysis revealed that isolates collected from the same hosts and/or geographic origins were often grouped together. For example, several isolates from natural environments were grouped with isolates from nearby agricultural areas. On the other hand, 2 geographically distant populations collected from the same host plant had similar genotypes. Our results suggested that migration of the pathogen could be facilitated naturally via drainage systems or by human activity in the transport of agricultural materials.

Molecular identification of oomycetes related to horticultural crops in Southern Sumatera and Java, Indonesia

“…Many horticultural plants are affected by oomycetes. As soil and water-borne pathogens, it can easily spread due to trade or transporting the planting materials (Afandi et al, 2018). However, the report on the pathogen infection in horticultural plants in Indonesia was still limited.…”

Diversity of aquatic Pythium and Phytopythium spp. from rivers and a pond of Gifu city, Japan

“…P. torulosum has also been isolated from aquatic habitats (Coker and Patterson, 1927). Recently, Afandi et al, (2018) reported that Pythium "group F" and the asexual isolate of Phytopythium helicoides were isolated several times from aquatic habitats. Therefore, current results of isolation of such species from water are in agreement with the previous studies.…”

Improving Containerized Nursery Crop Sustainability: Effects of Conservation-driven Adaptations in Soilless Substrate and Water Use on Plant Growth and Soil-borne Disease Development

“…For example, a Florida survey found that participating nurseries used 16 different substrate components, resulting in 26 different mixtures (Yeager and Newton, 2001). Peat moss has been a component of transplant and potting media for containerized vegetable and ornamental crops for the last 90 years (Alexander et al, 2008). It became a major component when it replaced the heavy and difficult-tosource loams and production of containerized plants increased (Alexander et al, 2008).…”

“…Peat moss has been a component of transplant and potting media for containerized vegetable and ornamental crops for the last 90 years (Alexander et al, 2008). It became a major component when it replaced the heavy and difficult-tosource loams and production of containerized plants increased (Alexander et al, 2008). Peat has many advantages, including abundance and affordability, high water holding and ion exchange capacity, decomposition resistance, low weight, and the relative ability to adsorb and release nutrients added as fertilizers (Bachmann et al, 2018;Barrett et al, 2016;Kingston et al, 2017;Robbins and Evans, 2011).…”

“…However, in many regions peat is harvested from wetland ecosystems at rates deemed unsustainable; furthermore, peat extraction releases stable, sequestered carbon into the active carbon cycle, exacerbating climate change (Barber, 1993;Barkham, 1993;Cleary et al, 2005;Dunn and Freeman, 2011;Huth et al, 2022). As a result, there has been increasing pressure on legislators, retailers, and growers to reduce the environmental impact of containerized nursery and greenhouse operations (Alexander et al, 2008), which has in turn led to exploration of alternative materials that can be produced more sustainably than peat (Evans and Stamps, 1996;Frenkel et al, 2017).…”