Molecular Markers Associated to Two Non-allelic Genic Male Sterility Genes in Peppers (Capsicum annuum L.)

Abstract

Male sterility is of high importance in hybrid seed production of hot and sweet peppers. Genic (or nuclear) male sterility (GMS) is a simply inherited (usually monogenic recessive) and highly stable trait. However, one major disadvantage of using GMS is 1:1 segregation of male sterile to male fertile plants in every subsequent generation. Molecular markers tightly linked to genic male sterility (ms) genes would facilitate an efficient and rapid transfer of ms genes into different genetic backgrounds through marker-assisted backcrossing. The two non-allelic genic male sterility genes ms3 and msw in hot and sweet pepper backgrounds, respectively, are monogenic recessive. Genotyping by sequencing (GBS) in an F2 population segregating for ms3 gene in hot pepper and in an F6 inbred near-isogenic line (NIL) population segregating for msw gene in sweet pepper yielded 9,713 and 7,453 single nucleotide polymorphism markers, respectively. Four candidate SNPs co-segregating with ms3 gene and one co-segregating with msw gene were identified by bulk segregant analysis and physically mapped to chromosomes 1 and 5, respectively. In hot pepper, two markers [HPGMS2 (CAPS) and HPGMS3 (dCAPS)] located 3.83 cM away from the ms3 gene and in sweet pepper the dCAPS marker SPGMS1 co-segregated (completely linked) with the msw gene were developed. These markers will increase the efficacy of the male sterility genes for pepper breeding, as they can be useful in developing the genic male sterile lines in parental inbred lines of commercial hybrids through marker-assisted backcrossing, hybrid seed production, and genetic purity testing of hybrid seeds.

Genomics and Marker-Assisted Improvement of Vegetable Crops

“…Capsicum annuum "CM334" is an important source of resistance to P. capsici, and has been utilized by pepper breeders. Several QTLs for resistance to various P. capsici isolates have been detected in different C. annuum genetic backgrounds (Kim et al, 2008;Naegele et al, 2014;Rehrig et al, 2014;Siddique et al, 2019). A QTL on chromosome 5 appears to be a major genetic factor involved in resistance to P. capsici (Mallard et al, 2013;Liu et al, 2014;Rehrig et al, 2014;Siddique et al, 2019).…”

“…Both genic male sterile (GMS) and cytoplasmic male sterile (CMS) systems are utilized for hybrid seed production in pepper (Jo et al, 2016;Jeong et al, 2018). Several molecular markers linked to genes controlling GMS, such as ms k (Lee et al, 2010a), ms1 (Lee et al, 2010b;Jeong et al, 2018), ms3 (Lee et al, 2010c;Naresh et al, 2018), ms8 (Bartoszewski et al, 2012), ms w (Naresh et al, 2018), and msc1 (Cheng et al, 2018), have been developed and used in MAS for hybrid seed production. However, CMS remains the preferred system for hybrid seed production provided that CMS is stable and restorer genes/factors (Rfs) are available (Swamy et al, 2017).…”

“…Breeding programs are taking advantage of rapid progress in the precision and speed of NGS technologies. Reduced representation sequencing approaches, including GBS, DArTseq, and SLAF-seq, have allowed identification and analysis of a large number of genetic loci through high-throughput genome screening at a relatively low cost (Li et al, 2018;Naresh et al, 2018;Du et al, 2019;Siddique et al, 2019;Tamisier et al, 2020). Using C. annuum reference genomes (Qin et al, 2014;Kim et al, 2017b), genes governing economically important traits, such as disease resistance, pungency, male sterility, and morphological characteristics have been positioned (Jo et al, 2016;Nimmakayala et al, 2016;Han et al, 2016a;Cheng et al, 2018;Kim et al, 2017c).…”

A 163‐bp insertion in the Capana10g000198 encoding a MYB transcription factor causes male sterility in pepper (Capsicum annuum L.)

“…To date, a total of more than 20 GMS mutants, including ms1 to ms4 , ms6 to ms15 , msc‐1 , msc‐2 (Wang & Bosland, 2006), msk (Lee et al., 2010; Shifriss, 1973), ms w (Naresh et al., 2018), the GMS mutant from NW1 bell pepper (Lee et al., 2012) and the GMS mutant developed by interspecific hybridization and then by chemical mutagenesis (Huang et al., 2015), are documented in pepper. The majority of the above‐mentioned pepper GMS mutants are controlled by single recessive genes.…”

“…Partial allelism relationships between them have been tested and verified. For example, the ms1 to ms4 , ms6 to ms8 are non‐allelic to each other (Wang & Bosland, 2006), the ms1 , ms3 and ms10 are non‐allelic to each other (Jeong et al., 2018), the ms12 is non‐allelic to ms1 and ms2 (Shifriss, 1973), the ms3 is non‐allelic to ms w (Naresh et al., 2018), and the msc‐2 is non‐allelic to msc‐1 but most likely is allelic to ms1 (Cheng, Li, et al., 2020).…”