高溫下番茄花粉活性數量性狀基因座 PV03 之精細定位

Abstract

番茄 (Solanum lycopersicum) 為茄科 (Solanaceae) 草本植物，起源於南美洲西部。除了作為重要經濟作物外，番茄亦能作為模式植物，具備極高的研究潛力與學術價值。在氣候變遷下，番茄花粉對高溫相當敏感。因此，本研究使用 RIL_41 和 CA4 之番茄雜交族群，對高溫下維持花粉活性的數量性狀基因座pollen viability 03 (PV03) 進行精細定位。種植 1500 株 F2 世代植株，利用 KASP 基因型檢測方法篩選在 PV03 區間遺傳重組之植株，並利用 CAPS 分子標記檢測植株在更小區間的重組情形。於 F3 世代篩選同型結合基因型植株後，推進至 F4 世代。並測量 10 種不同基因型共 81 個家系，以及四個對照組 24TS201、24TS202、24TS203和 24TS204 之活性花粉數目 (viable pollen number)、總花粉數目 (total pollen number) 和花粉活性比例 (percentage of viable pollen)。花粉活性比例外表型之結果顯示，24TS201 (CA4) 和 24TS204 (RIL_41 x CA4 F1) 為不耐熱家系；24TS202 (CLN1621L) 和 24TS203 (RIL_41) 為耐熱家系。但在 81 個控制組家系中，僅 33 個家系可被歸類為耐熱或不耐熱家系。同時，在 PV03 區間基因型相同之植株外表型卻不盡相同，因而無法精細定位 PV03 所在的區間。未來 PV03 之精細定位研究應考量自然光照因素、增加實驗重複數，並控制試驗族群中其他可能影響花粉活性之基因，以達到更好的精細定位效果。

Tomato (Solanum lycopersicum) is an herbaceous plant originating from the western region of South America. In addition to being an important economic crop, tomato serves as a model plant with significant academic research value. Tomato pollen is highly sensitive to heat stress while facing climate change. This study utilized the tomato recombinant inbred lines (RILs) RIL_41 and CA4 to fine-map the pollen viability 03 (PV03) QTL which confers maintenance of pollen viability under heat stress. A total of 1,500 F2 plants were screened using the KASP genotyping method to identify recombinants within the PV03 region. Subsequently, five CAPS markers within the PV03 region were used to genotype these plants in the F2 generation, followed by the selection of homozygous genotypes in the F3 generation. A total of 81 F4 lines with different genotypes, along with 4 control lines 24TS201, 24TS202, 24TS203, and 24TS204, were evaluated for viable pollen number (VPN), total pollen number (TPN) and percentage of viable pollen (PVP). The results showed that 24TS201 (CA4) and 24TS204 (RIL_41 x CA4 F1) are heat-sensitive lines, while 24TS202 (CLN1621L) and 24TS203 (RIL_41) are heat-tolerant lines. However, only 33 out of 81 F4 lines could be categorized as heat-sensitive or heat-tolerant. Furthermore, plants with identical genotypes within the PV03 region exhibited different phenotypes of VPN and PVP, resulting in the failure of PV03 fine mapping. Future studies are suggested to consider the effects of natural light conditions, increase experimental replicates, and stabilize the genetic background by controlling for other genes that may influence pollen viability under heat stress.