Ren Deyong, Rao Yuchun, Huang Lichao, Leng Yujia, Hu Jiang, Lu Mei, Zhang Guangheng, Zhu Li, Gao Zhenyu, Dong Guojun, Guo Longbiao, Qian Qian, Zeng Dali
State Key Lab for Rice Biology, China National Rice Research Institute, Hangzhou, 310006, P. R. China.
College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, P. R. China.
Rice (N Y). 2016 Dec;9(1):4. doi: 10.1186/s12284-016-0076-7. Epub 2016 Feb 4.
High yield and quality determine the commercial potential of rice variety. Brown rice rate (BRR) is a key factor ensuring grain yield and quality in rice. So far, there were few reports about the genes that directly controlled the BRR in rice. Therefore, dissecting the genetic mechanism of the BRR genes can facilitate improving effective rice supply or edible grain yield.
A double haploid population derived from the cross between Taichung Native 1 (TN1) (an indica variety) and Chunjiang 06 (CJ06) (a japonica variety) was used to investigate the genetic basis of grain milling and appearance traits affecting the BRR. By using a constructed molecular linkage map, four quantitative trait loci (QTLs) for the BRR were detected on chromosomes 1, 8, 9, and 10, respectively. In addition, three QTLs for appearance traits, including grain weight and grain length/width ratio, were detected on chromosomes 6, 9 and 10, respectively. Chromosome segment substitution lines (CSSLs) were established at the qBRR-10 locus. Finally, the qBRR-10 was narrowed to a 39.5 kb region on chromosome 10. In this region, two candidate genes, LOC_Os10g32124 and LOC_Os10g32190, showed significantly differential expression in TN1 and CSSL1-2 compared with CJ06. Histocytological analysis suggested that cell size and hull thickness may be important factors for the BRR.
In the study, the qBRR-10 affected the BRR and was finally located to a region between two markers, P13 and P14. Two candidate genes were selected based on the expression difference between two parents, which facilitated the further cloning of the qBRR-10 gene and largely contributed to improve the grain yield and quality in rice.
高产和优质决定了水稻品种的商业潜力。糙米率是确保水稻产量和品质的关键因素。到目前为止，关于直接控制水稻糙米率的基因报道较少。因此，剖析糙米率基因的遗传机制有助于提高水稻有效供给或食用谷物产量。
利用台中本地1号（TN1，籼稻品种）和春江06（CJ06，粳稻品种）杂交衍生的加倍单倍体群体，研究影响糙米率的碾磨和外观性状的遗传基础。通过构建分子连锁图谱，分别在第1、8、9和10号染色体上检测到4个控制糙米率的数量性状位点（QTL）。此外，分别在第6、9和10号染色体上检测到3个控制外观性状的QTL，包括粒重和粒长宽比。在qBRR-10位点建立了染色体片段代换系（CSSL）。最后，将qBRR-10定位到第10号染色体上一个39.5 kb的区域。在该区域，两个候选基因LOC_Os10g32124和LOC_Os10g32190在TN1和CSSL1-2中与CJ06相比表现出显著差异表达。组织细胞学分析表明，细胞大小和颖壳厚度可能是影响糙米率的重要因素。
本研究中，qBRR-10影响糙米率，最终定位在两个标记P13和P14之间的区域。基于两个亲本之间的表达差异选择了两个候选基因，这有助于进一步克隆qBRR-10基因，并在很大程度上有助于提高水稻的籽粒产量和品质。
