Challenges and Strategies for Breeding Resistance in Capsicum annuum to the Multifarious Pathogen, Phytophthora capsici.

Derek W Barchenger,Kurt H Lamour,Paul W Bosland

doi:10.3389/fpls.2018.00628

Derek W Barchenger, Kurt H Lamour + Show 1 more

Open Access

https://doi.org/10.3389/fpls.2018.00628

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Abstract

Phytophthora capsici is the most devastating pathogen for chile pepper production worldwide and current management strategies are not effective. The population structure of the pathogen is highly variable and few sources of widely applicable host resistance have been identified. Recent genomic advancements in the host and the pathogen provide important insights into the difficulties reported by epidemiological and physiological studies published over the past century. This review highlights important challenges unique to this complex pathosystem and suggests strategies for resistance breeding to help limit losses associated with P. capsici.

Highlights

The soil-borne oomycete plant pathogen Phytophthora capsici (Leon.) is the most devastating pathogen to chile pepper production
This population started with diploid parents and the authors report elevated heterozygosity across the mating type region” (MTR) for the A2 mating type relative to the A1 mating type followed intensive inbreeding. This finding was supported by Barchenger et al (2017), who found that the A1 isolates collected in Taiwan were largely diploid and the A2 isolates were generally triploid or higher ploidy. Both A1 and A2 mating types of P. capsici have been widely identified within the same field (Ristaino, 1990; Pan, 1997; Parra and Ristaino, 1998, 2001; Lamour and Hausbeck, 2000, 2001a, 2002; Ploetz R. et al, 2001; Fernandez-Pavia et al, 2004; Islam et al, 2004; Ann et al, 2008; Donahoo and Lamour, 2008; Glosier et al, 2008; French-Monar et al, 2009; Sheu et al, 2009; Dunn et al, 2010; Gobena et al, 2012a; Yin et al, 2012; Jiang et al, 2015; Barchenger et al, 2017), increasing the probability of sexual reproduction leading to new races and recombinant oospores resulting in persistence across growing seasons
This was recently demonstrated in Taiwan (Barchenger et al, 2017), where we conducted targeted sequencing on P. capsici isolates collected in Taiwan and analyzed the data in terms of the virulence phenotypes developed based on the New Mexico Recombinant Inbred Lines (NMRIL)

Summary

INTRODUCTION

The soil-borne oomycete plant pathogen Phytophthora capsici (Leon.) is the most devastating pathogen to chile pepper production. This finding was supported by Barchenger et al (2017), who found that the A1 isolates collected in Taiwan were largely diploid and the A2 isolates were generally triploid or higher ploidy Both A1 and A2 mating types of P. capsici have been widely identified within the same field (Ristaino, 1990; Pan, 1997; Parra and Ristaino, 1998, 2001; Lamour and Hausbeck, 2000, 2001a, 2002; Ploetz R. et al, 2001; Fernandez-Pavia et al, 2004; Islam et al, 2004; Ann et al, 2008; Donahoo and Lamour, 2008; Glosier et al, 2008; French-Monar et al, 2009; Sheu et al, 2009; Dunn et al, 2010; Gobena et al, 2012a; Yin et al, 2012; Jiang et al, 2015; Barchenger et al, 2017), increasing the probability of sexual reproduction leading to new races and recombinant oospores resulting in persistence across growing seasons. More than 81% of the Capsicum genome consists of transposons, which is high compared to closely related tomato (50%) and potato (47%) (Qin et al, 2014)

Screening Methodology

Findings

CONCLUSION