Li Junzhou, Xie Yan, Dai Anyong, Liu Lifeng, Li Zichao
Key Laboratory of Crop Genomics and Genetic Improvement of Ministry of Agriculture and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, China.
J Genet Genomics. 2009 Mar;36(3):173-83. doi: 10.1016/S1673-8527(08)60104-6.
Phosphorous (P) deficiency is a major restraint factor for crop production and plants have developed several mechanisms to adapt to low P stress. In this study, a set of 271 introgression lines (ILs) were used to characterize the responses of seedlings to low P availability and to identify QTLs for root traits, biomass, and plant height under P-deficiency and P-sufficiency conditions. Plant height, total dry weight, shoot dry weight, and root number were inhibited under P-deficiency, whereas maximum root length (MRL) and root-shoot ratio (RS) were induced by P-deficiency stress. Relative MRL (RMRL, the ratio of MRL under P-deficiency to MRL under P-sufficiency condition) and relative RS (RRS) were used to evaluate P-deficiency tolerance at the seedling stage. A total of 24 additive QTLs and 29 pairs of epistatic QTLs were detected, but only qRN4 was detected in both conditions. This suggested that different mechanisms may exist in both P supply levels. QTLs for adaptive traits (RMRL, RRS, RRV, and RRDW) and qRN4 consistently expressed to increase trait stability may contribute to P-deficiency tolerance. Twelve intervals were cluster regions of QTLs for P-deficiency tolerance, and one QTL (qRRS8) showed pleiotropic effects on P-deficiency tolerance and drought tolerance. These interesting QTLs can be used in marker-assisted breeding through the target ILs.
磷（P）缺乏是作物生产的主要限制因素，植物已发展出多种机制来适应低磷胁迫。在本研究中，一组271个导入系（ILs）被用于表征幼苗对低磷有效性的响应，并鉴定在缺磷和磷充足条件下根系性状、生物量和株高的QTL。在缺磷条件下，株高、总干重、地上部干重和根数受到抑制，而最大根长（MRL）和根冠比（RS）则由缺磷胁迫诱导。相对MRL（RMRL，缺磷条件下的MRL与磷充足条件下的MRL之比）和相对RS（RRS）用于评估苗期的耐缺磷性。共检测到24个加性QTL和29对上位性QTL，但仅在两种条件下均检测到qRN4。这表明在两种磷供应水平下可能存在不同的机制。适应性性状（RMRL、RRS、RRV和RRDW）的QTL和始终表达以增加性状稳定性的qRN4可能有助于耐缺磷性。12个区间是耐缺磷性QTL的聚类区域，一个QTL（qRRS8）对耐缺磷性和耐旱性表现出多效性。这些有趣的QTL可通过目标导入系用于标记辅助育种。
