Wang Jie, Dun Xiaoling, Shi Jiaqin, Wang Xinfa, Liu Guihua, Wang Hanzhong
Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan, China.
Front Plant Sci. 2017 Sep 29;8:1709. doi: 10.3389/fpls.2017.01709. eCollection 2017.
As the major determinant for nutrient uptake, root system architecture (RSA) has a massive impact on nitrogen use efficiency (NUE). However, little is known the molecular control of RSA as related to NUE in rapeseed. Here, a rapeseed recombinant inbred line population (BnaZNRIL) was used to investigate root morphology (RM, an important component for RSA) and NUE-related traits under high-nitrogen (HN) and low-nitrogen (LN) conditions by hydroponics. Data analysis suggested that RM-related traits, particularly root size had significantly phenotypic correlations with plant dry biomass and N uptake irrespective of N levels, but no or little correlation with N utilization efficiency (NUtE), providing the potential to identify QTLs with pleiotropy or specificity for RM- and NUE-related traits. A total of 129 QTLs (including 23 stable QTLs, which were repeatedly detected at least two environments or different N levels) were identified and 83 of them were integrated into 22 pleiotropic QTL clusters. Five RM-NUE, ten RM-specific and three NUE-specific QTL clusters with same directions of additive-effect implied two NUE-improving approaches (RM-based and N utilization-based directly) and provided valuable genomic regions for NUE improvement in rapeseed. Importantly, all of four major QTLs and most of stable QTLs (20 out of 23) detected here were related to RM traits under HN and/or LN levels, suggested that regulating RM to improve NUE would be more feasible than regulating N efficiency directly. These results provided the promising genomic regions for marker-assisted selection on RM-based NUE improvement in rapeseed.
作为养分吸收的主要决定因素，根系结构（RSA）对氮素利用效率（NUE）有巨大影响。然而，关于油菜中与NUE相关的RSA的分子调控知之甚少。在此，利用一个油菜重组自交系群体（BnaZNRIL），通过水培法研究了高氮（HN）和低氮（LN）条件下的根系形态（RM，RSA的一个重要组成部分）和与NUE相关的性状。数据分析表明，无论氮水平如何，与RM相关的性状，特别是根大小与植物干生物量和氮吸收具有显著的表型相关性，但与氮利用效率（NUtE）无相关性或相关性很小，这为鉴定与RM和NUE相关性状具有多效性或特异性的QTL提供了可能。共鉴定出129个QTL（包括23个稳定QTL，在至少两个环境或不同氮水平下重复检测到），其中83个被整合到22个多效性QTL簇中。五个RM-NUE、十个RM特异性和三个NUE特异性QTL簇具有相同方向的加性效应，暗示了两种提高NUE的方法（基于RM和直接基于氮利用），并为油菜NUE的提高提供了有价值的基因组区域。重要的是，这里检测到的四个主要QTL和大多数稳定QTL（23个中的20个）都与HN和/或LN水平下的RM性状相关，这表明调节RM以提高NUE比直接调节氮效率更可行。这些结果为油菜基于RM的NUE改良的标记辅助选择提供了有前景的基因组区域。
