利用Dualex葉綠素儀研究鷹嘴豆的耐熱性

更新時間：2022-05-07　點擊量：2109

Dualex便攜式智能氣象-葉綠素-花青素-黃酮醇測量儀

在氣候變化的背景下，鷹嘴豆（Cicer arietinum L.）繁殖期的熱應激導致了顯著的產量損失。為了確定與熱應激耐受性相關的基因組區域，使用測序基因分型方法對源自DCP 92-3（熱敏感）和ICCV 92944（熱耐受）的重組自交系群體進行基因分型，并在正常和晚播或熱應激環境下連續兩年（2017年和2018年）進行評估。構建了包含788個單核苷酸多態性標記的高密度遺傳圖譜，標記跨度為1125cm。利用復合區間作圖，13個性狀中的12個共鑒定出77個qtl（37個主效qtl和40個副效qtl）。CaLG07上的一個基因組區域包含數量性狀位點（QTL），解釋了從結莢到結莢的天數、100粒重的表型變異>30%，解釋了>10%PVE的氮平衡指數。此外，我們還報道了性狀（葉綠素含量、氮平衡指數、歸一化差異營養指數和細胞膜穩定性等生理性狀）的主要QTL。此外，QTL區域中編碼熱休克蛋白基因、熱休克轉錄因子的32個候選基因與花粉特異性基因以及開花時間調控有關。本研究報告的主要QTL經驗證后，可能有助于開發耐熱優良品系或品種的分子育種。

關鍵詞：鷹嘴豆、熱應激、測序基因分型、歸一化差異植被指數、結莢天數

Major QTLs and Potential Candidate Genes for Heat Stress Tolerance Identified in Chickpea (Cicer arietinum L.)

In the context of climate change, heat stress during the reproductive stages of chickpea (Cicer arietinum L.) leads to significant yield losses. In order to identify the genomic regions responsible for heat stress tolerance, a recombinant inbred line population derived from DCP 92-3 (heat sensitive) and ICCV 92944 (heat tolerant) was genotyped using the genotyping-by-sequencing approach and evaluated for two consecutive years (2017 and 2018) under normal and late sown or heat stress environments. A high-density genetic map comprising 788 single-nucleotide polymorphism markers spanning 1,125 cM was constructed. Using composite interval mapping, a total of 77 QTLs (37 major and 40 minor) were identified for 12 of 13 traits. A genomic region on CaLG07 harbors quantitative trait loci (QTLs) explaining >30% phenotypic variation for days to pod initiation, 100 seed weight, and for nitrogen balance index explaining >10% PVE. In addition, we also reported for the first time major QTLs for proxy traits (physiological traits such as chlorophyll content, nitrogen balance index, normalized difference vegetative index, and cell membrane stability). Furthermore, 32 candidate genes in the QTL regions that encode the heat shock protein genes, heat shock transcription factors, are involved in flowering time regulation as well as pollen-specific genes. The major QTLs reported in this study, after validation, may be useful in molecular breeding for developing heat-tolerant superior lines or varieties.

Keywords: chickpea, heat stress, genotyping-by-sequencing, normalized difference vegetation index, days to pod initiation