Genetic characterization of the late blight resistant locus qPh2.1 in tomato

本研究室先前的數量性狀基因座遺傳定位研究指出，野生番茄L3708 (Solanum pimpinellifolium L.) 除了在第九對染色體具有晚疫病抗病基因Ph-3以外，於第二對染色體上亦具有另一個抗病基因qPh2.1。延續先前研究結果，本研究使用與先前研究相同的野生番茄L3708與栽培番茄T3224雜交族群，以其衍生之自交F3:4子代為接種材料進行研究。並設定兩個研究目標：(1) Ph-3抗病基因的精確定位；(2) 新抗病基因qPh2.1對於晚疫病抗病能力的確認，並評估qPh2.1基因座的遺傳特性。 研究結果指出，qPh2.1確實能賦予番茄對晚疫病之抗性，其抗病對偶基因型相對於感病對偶基因型為隱性。根據番茄全基因體組參照序列SL 2.5，本研究將Ph-3抗病基因定位於番茄第九對染色體鹼基序列71,356,855 bp至71,501,998 bp區間；qPh2.1則被定位於番茄第二對染色體鹼基序列 28,042,265 bp的前方染色體區域。Our previous QTL mapping study showed that the wild tomato accession L3708 (Solanum pimpinellifolium L.) harbors a new late blight resistant gene qPh2.1 on chromosome 2, in addition to the Ph-3 gene on chromosome 9. The aims of present study were as following: (1) Ph-3 fine mapping; (2) genetic characterization of the resistance of qPh2.1. In the current study, the qPh2.1 resistance to late blight disease was validated and characterized using isogenic lines derived from the previous F2:3 genetic mapping population which was generated using L3708 as the resistant parent. Our results indicated that the resistant allele of qPh2.1 was recessive to the susceptible allele. The qPh-3 gene was delimited in the region between 71,356,855 bp to 71,501,998 bp; and the qPh2.1 gene was delimited in the chromosomal region ahead of 28,042,265 bp on chromosome 2, according to the tomato SL 2.5 genomic reference sequences