利用分子標幟輔助導入Saltol QTL提升耐鹽品系CWY981126耐鹽性之可行性

The Introgressionof Saltol QTLs into Salt Tolerant Line CWY981126 to Increase Its Salinity Tolerance by Using Marker-Assisted Selection

郭介煒(Chieh-Wei Kuo) ； 溫甯翔(Ning-Hsiang Wen) ； 郭素真(Su-Chen Kuo) ； 林彥蓉(Yann-Rong Lin) ； 吳永培(Yong-Pei Wu)

《作物、環境與生物資訊》 12卷4期 (2015/12) Pp. 198-217

https://doi.org/10.30061/CEB.201512_12(4).0004

摘要

作物品種之耐鹽特性，有助於其生存於含鹽分較高之農地，亦為氣候變遷情境下作物耐抗非生物性逆境之一項因應調適策略。本研究乃利用耐鹽品系CWY981126為輪迴親，耐鹽秈稻(indica)品種'Pokkali'為貢獻親，利用分子標幟輔助回交法將'Pokkali'之Saltol QTL導入CWY981126品系中，探討是否導入Saltol QTL可增加CWY981126之耐鹽性。過程中各回交世代先進行Saltol QTL之前景選拔，獲選後代再經分子標幟輔助進行背景選拔。試驗結果發現，帶有Saltol QTL對偶基因之回交子代，其BC_1F_1、BC_2F_1及BC_2F_2世代遺傳背景回復至輪迴親的比率分別為73.2、85.3及88.8%，而在BC_2F_2子代中最高者可達97%，近似於傳統回交育種理論值87.5%。又BC_2F_2子代於五葉齡時以200mM NaCl模擬鹽分逆境處理後，結果發現帶有'Pokkali'之Saltol QTL同型合子、'Pokkali'/CWY981126之Saltol QTL異型合子及CWY981126同型合子等三者間之耐鹽性無差異存在，顯示導入Saltol QTLs並無法提升耐鹽品系CWY981126的耐鹽表現。而以'Pokkali'、CWY981126、'IR64'及9個BC_2F_3品系於五葉齡及最高分蘗期後等時期進行100、150、200、250及300mM NaCl模擬鹽分逆境處理，結果發現各品系間耐鹽等級達顯著差異水準，其中STP3有較佳的耐鹽表現。而相同材料分別於五葉齡及最高分蘗期以200 mM NaCl進行模擬鹽分逆境評估，結果五葉齡時以品系STP3的耐鹽性表現最佳，而最高分蘗期則以STP7的耐鹽性表現最佳，甚至優於其耐鹽親本'Pokkali'。由結果顯示，本試驗雖已順利將Saltol QTL導入CWY981126中，惟BC_2F_3回交品系之耐鹽性並未能有效提昇，其原因可能是CWY981126耐鹽性之機制與Saltol QTL相似，由於欠缺累加效應的現象存在，致使導入Saltol QTL之效益無法顯現。

關鍵字

分子標幟輔助選拔 ； 耐鹽 ； 水稻

並列摘要

In this study, a salt-tolerant japonica line CWY981126 was used as the recurrent parent and a salt-tolerant indica variety 'Pokkali' with Saltol gene was used as the donor parent. Marker-assisted backcross was applied to introgress Saltol QTL from 'Pokkali' into CWY981126 to verify whether the salinity tolerance of CWY981126 was improved. For each backcross generation, the foreground selection of Saltol QTL was conducted first, and the selected progenies were subsequently subjected to background selection by marker-assisted selection. Among the backcrossed progenies carrying Saltol QTL, the average recovery rates of genetic background of the recurrent parent in BC_1F_1, BC_2F_1 and BC_2F_2 generations were 73.2, 85.3 and 88.8%, respectively. Moreover, the highest recovery rate was up to 97% in BC2F2. As compared to the theoretical value of traditional backcross breeding of BC_2F_1, 87.5%, marker-assisted selection could recover genomes of the recurrent parent CWY981126 almost same as traditional backcross breeding. When the progenies of BC_2F_2 were treated with 200 mM NaCl at the fifth-leaf stage, results showed that there was no difference among homozygotes of 'Pokkali' Saltol QTL, heterozygotes of 'Pokkali'/CWY981126 Saltol QTL, and homozygotes of CWY981126. It implied that the salinity tolerance of CWY981126 was not enhanced by introgressing Saltol QTL from 'Pokkali'. When 'Pokkali', CWY981126 and nine lines of BC2F3 were treated with solutions of five concentrations of NaCl at 100, 150, 200, 250 and 300 mM, respectively, at the fifth-leaf stage and after maximum tillering stage, results indicated that the salt-tolerant levels varied significantly among different lines. The line STP3 had the highest salt tolerance. At the concentration of 200 mM NaCl, STP3 performed the best to tolerate salt stress at the fifth-leaf stage, while STP7 had the highest salt tolerance after maximum tillering stage, even higher than 'Pokkali'. Although Saltol QTL seemed successfully introgressed into CWY981126 in this study, the salinity tolerance of backcross lines of BC_2F_3 was not improved effectively, suggesting that the salt-tolerant mechanism of CWY981126 might be similar to the mechanism of Saltol QTL. Therefore, there was no additive effect of introgression of Saltol QTLs.

並列關鍵字

Marker-assisted selection (MAS) ； Salt tolerance ； Rice