Population Structure of Phytophthora nicotianae Reveals Host-Specific Lineages on Brinjal, Ridge Gourd, and Tomato in South India

Abstract

Severe outbreaks of Phytophthora fruit rot on brinjal, ridge gourd, and tomato have been observed since 2011 in Andhra Pradesh, Karnataka, Telangana, and Tamil Nadu states of India. Therefore, 76 Phytophthora nicotianae isolates, recovered from brinjal (17), ridge gourd (40), and tomato (19) from different localities in these states during the June to December cropping season of 2012 and 2013, were characterized based on phenotypic and genotypic analyses and aggressiveness on brinjal, tomato, and ridge gourd. All brinjal and ridge gourd isolates were A2, while tomato isolates were both A1 (13) and A2 (6). All isolates were metalaxyl sensitive. In addition, isolates were genotyped for three mitochondrial (ribosomal protein L5-small subunit ribosomal RNA [rpl5-rns], small subunit ribosomal RNA-cytochrome c oxidase subunit 2 [rns-cox2], and cox2+spacer) and three nuclear loci (hypothetical protein [hyp], scp-like extracellular protein [scp], and beta-tubulin [β-tub]). All regions were polymorphic but nuclear regions were more variable than mitochondrial regions. The network analysis of genotypes using the combined dataset of three nuclear regions revealed a host-specific association. However, the network generated using mitochondrial regions limited such host-specific groupings only to brinjal isolates. P. nicotianae isolates were highly aggressive and produced significantly (P ≤ 0.01) larger lesions on their respective host of origin than on other hosts. The results indicate significant genetic variation in the population of P. nicotianae, leading to identification of host-specific lineages responsible for severe outbreaks on brinjal, ridge gourd, and tomato.

Phylogenetic analyses and cross‐infection studies of Phytophthora species infecting cacao and durian in South‐Central Mindanao, Philippines

“…isolates suggest pathogen's adaptability and efficiency in infecting its native hosts such as durian and cacao. The result was similar to the findings of Chowdappa et al (2016) where different genotypes of P. nicotianae from brinjal, ridge gourd and tomato formed a hostspecific groupings of the isolates in the phylogenetic tress generated using the combined dataset of three mitochondrial regions. Wyand and Brown (2003) also observed the grouping of isolates according to their host in the phylogenetic analysis of different formae speciales of the Blumeria graminis using rDNA ITS and βtubulin (β-tub) genes, which was further confirmed through AFLP analysis (Borah et al, 2018).…”

Ethyl acetate produced by Hanseniaspora uvarum is a potential biocontrol agent against tomato fruit rot caused by Phytophthora nicotianae

“…VOCs are substances with a low molecular weight (<300 Da), high vapor pressure (≥0.01 kPa at 20 • C), and low water solubility (Pagans et al, 2006;Delgado et al, 2021). The VOCs synthesized by microbes contains a variety of compounds such as esters, alcohols and aromatic compounds (de Boer et al, 2019). The present study revealed that the volatiles produced by H. uvarum MP1861 contained ethyl acetate, isopentyl alcohol (1-butanol, 3-methyl-, acetate), and phenylethyl alcohol.…”

“…Phytophthora nicotianae , first isolated from tobacco, is an important pathogen because it causes severe damage to a particularly large number of host plants (Panabieres et al, 2016 ). More than 255 plant species can be infected by P. nicotianae , including tomato, tobacco, potato, citrus, and eggplant (Chowdappa et al, 2016 ; Panabieres et al, 2016 ). At present, the application of fungicides, such as formanyl, hymexazol, and dimethomorph, is the main method to prevent the occurrence of plant diseases caused by P. nicotianae (Han et al, 2019 ).…”

Characterization of Phytophthora nicotianae isolates from tobacco plants (Nicotiana tabacum) in Colombia

“…-P. nicotianae (Sullivan et al, 2010). Host specific lineages have been reported for P. nicotianae, evidence suggests that isolates may be more aggressive in their host of origin than in other plant hosts and clonality prevails in pathogen populations suggesting asexual dispersion (Mammella et al, 2013;Biasi et al, 2016;Chowdappa et al, 2016). Lamour et al (2003) evaluated isolates from different geographic areas and observed a similar compatibility between them and the host, a characteristic maybe due to asexual reproduction of P. nicotianae.…”