Neoerysiphe sechii (Ascomycota: Erysiphales): A new species of powdery mildew found on Sechium edule and Sechium mexicanum (Cucurbitaceae) in Mexico

Abstract

A novel species of powdery mildew, Neoerysiphe sechii sp. nov., has been proposed based on host, morphological characteristics, and gene sequences. The new species was found on chayote (Sechium edule) and a wild species, chayotillo (S. mexicanum), in Veracruz, Mexico. This novel species was identified as a member of Neoerysiphe, based on the morphological characteristics of the anamorph: catenescent conidia, lobed appressoria, and Striatoidium-type conidia. No teleomorph was observed. Neoerysiphe sechii is distinguished by foot cells that are frequently cylindrical with a slight widening at the base, a feature not observed previously in other species in the genus. An Erysiphales-specific primer was designed for the 5′ end of the ITS region of the nuclear rDNA. Independent and concatenated phylogenetic analyses with our rDNA sequences and sequences available in GenBank for Neoerysiphe spp. confirmed that the powdery mildew specimens found in Sechium spp. form an independent and strongly supported lineage. This is the first report of a Neoerysiphe species causing powdery mildew on members of Cucurbitaceae, and it is the second species reported from Mexico after N. cumminsiana. Neoerysiphe sechii is found on cultivated and endemic hosts in Mexico, suggesting that the fungus itself may be endemic.

Combined genomic, transcriptomic, and metabolomic analyses provide insights into chayote (Sechium edule) evolution and fruit development

“…Chayote ( Sechium edule ) is a diploid perennial herbaceous climbing plant with 28 chromosomes (2 n = 2 x = 28) 1 that belongs to the Cucurbitaceae family 2 . The chayote fruit is a gourd that is consumed as a vegetable, also called vegetable pear, chuchu, pear squash, or sayote 3 , 4 , and the tubers are also utilized as food source.…”

Powdery mildew of chayote (Sechium edule) caused by Podosphaera xanthii race 2 in Brazil

“…G. tabaci ) (Farr & Rossman, 2023). More recently, Neoerysiphe sechii was identified as a new chayote‐specific species in Mexico (Gregorio‐Cipriano et al, 2020). In Brazil, distinct causal agents of chayote PM have been reported, but none of them with support of morphological and molecular data (Mendes & Urben, 2023).…”

“…. sechii (a new PM-inducing species from Mexico)(Gregorio- Cipriano et al, 2020). Distinct causal agents of chayote PM have been reported in Brazil, but none of them with support of morphological and molecular data(Mendes & Urben, 2023).…”

Identificación molecular de los tipos de compatibilidad en poblaciones de Podosphaera xanthii (Erysiphaceae) infectando cucurbitáceas en Veracruz, México

“…Para comprobar que las amplificaciones correspondían a los idiomorfos de P. xanthii, se seleccionaron y secuenciaron dos de los productos de PCR obtenidos de MAT1-1-1 y dos de MAT1-2-1. La secuenciación se realizó siguiendo los procedimientos previamente descritos por Gregorio-Cipriano et al (2020. Se corroboró la afinidad de las secuencias obtenidas con las secuencias del MAT1-1-1 (KJ438825, HQ171903) y MAT1-2-1 (KJ438826,…”