Population Genetic Analysis of Phytophthora parasitica From Tobacco in Chongqing, Southwestern China

Abstract

Tobacco black shank, caused by Phytophthora parasitica, is one of the most notorious tobacco diseases and causes huge economic losses worldwide. Understanding the genetic variation of P. parasitica populations is essential to the development of disease control measures. In this research, 210 simple sequence repeat (SSR) markers for P. parasitica were identified, 10 of which were polymorphic among nine reference strains. We further performed population genetic analysis of 245 P. parasitica isolates randomly collected from tobacco fields in Chongqing for mating type, molecular variation at 14 SSR loci (four of which were identified previously), and sensitivity to the fungicide metalaxyl. The results showed that the A2 mating type was dominant and no A1 mating type isolate was discovered. SSR genotyping distinguished 245 P. parasitica isolates into 46 genotypes, four of which were dominant in the population. Low genotypic diversity and excess heterozygosity were common in nearly all of the populations from Chongqing. Population analysis showed that no differentiation existed among different populations. All isolates tested were highly sensitive to metalaxyl. Taken together, our results showed that the P. parasitica populations from tobacco fields in Chongqing belonged to a clonal lineage and were highly sensitive to metalaxyl.

Two Phytophthora parasitica cysteine protease genes, PpCys44 and PpCys45, trigger cell death in various Nicotiana spp. and act as virulence factors

“…N. benthamiana seeds were sown on soil in a matrix and cultured in a Phytotron with a 13 hr light:11 hr dark photoperiod for about 30–40 days. P. parasitica strains were routinely maintained on 5% carrot agar (CA) plates (Zhang et al , ). Incubation conditions were as follows: 23 °C, darkness.…”

Population genetics of Phytophthora species based on short sequence repeat (SSR) marker: a review of its importance and recent studies

“…These reports are also in line with another study that revealed a low population genetic diversity of P. parasitica in Chongqing resulting from clonality, as there is only MT A2 reported in the population. The limited population variation in this population is most likely from random mutation [48]. The occurrence of sexual reproduction in a population does not always result in genetic recombination.…”

Comparative Genome Analysis Across 128 Phytophthora Isolates Reveal Species-Specific Microsatellite Distribution and Localized Evolution of Compartmentalized Genomes

“…There are many important biological features attributed to SSRs such as codominance, multiallelic nature, and genetic markers just to name a few. These features are used for determining the mating type, genome reconstruction, disease dynamics, and determination of population structures ( Schena et al, 2008 ; Biasi et al, 2016 ; Stewart et al, 2016 ; Engelbrecht et al, 2017 ; Parada-Rojas and Quesada-Ocampo, 2018 ; Hieno et al, 2019 ; Zhang et al, 2019 ; Guo et al, 2021 ). The available literature indicates studies involving fewer species and lacks a broader view.…”