小麦主栽品种济麦22与良星99的基因组序列多态性比较分析

Jimai 22 and Liangxing 99 are high-yield wheat varieties widely planted in the North Huang-Huai Rivers Valley Winter Wheat Zone and Northern Winter Wheat Zone in China, and are currently used as important parents in wheat breeding programs. Although the origins and pedigrees of Jimai 22 and Liangxing 99 are different, they are highly similar in many important agronomic traits, yield-associated traits, and so on. To identify the genomic differences between the two varieties, we performed whole-genome sequencing using the Illumina HiSeq2500 platform, with an average sequencing depth of 5.8×. We aligned the raw sequencing data against the Chinese Spring reference genome and identified the difference of copy-number variation (CNV) regions, single-nucleotide polymorphisms (SNPs) and InDels in sequence between the two varieties. Lengths of 466 Mb CNV intervals were shared by the two varieties. The lengths of cultivar-specific CNV intervals in Jimai 22 and Liangxing 99 were 91 Mb and 45 Mb, respectively, and these intervals are mainly located on chromosomes 2B and 4B. Beyond the CNV intervals, 1,547,371 SNPs and 137,817 InDels were different between the two cultivars. Based on the distribution of SNP densities in the intervals, we identified the polymorphic hotspot regions on chromosomes 1D, 2B, and 4B, making up 14.2% of the whole genome. The sequences of five previous cloned dwarf genes and spike length related genes were investigated, and two genes located in the polymorphic hotspot regions were detected with the frame shift variations. This study provides an important guidance for evaluating the genetic differences between two wheat varieties in the genomic level, and also identified both genetic similarity regions and polymorphic hotspot regions between Jimai 22 and Liangxing 99, which provided a valuable genetic information for future genetic improvement utilizing Jimai 22 and Liangxing 99 as parents.     

Pm52——小麦品种良星99抗白粉病基因的有效性

良星99是黄淮冬麦区和北部冬麦区推广的抗白粉病冬小麦品种,其抗白粉病基因位于2BL染色体,已被命名为Pm52。利用来自不同小麦生产区的123个小麦白粉菌菌株进行抗性鉴定,良星99可抗80%的菌株。2012-2016年连续5个生长季抗性鉴定中,良星99在成株期对接种的白粉菌混合菌株都表现免疫或高抗。采用Pm52基因紧密连锁分子标记Xgwm120和27个菌株对10个利用良星99培育的品系进行分子检测和抗性分析发现,衡4568、邯农2312、中信麦99和DH51302可能携带Pm52基因,而郑麦369和冀麦729的白粉病抗性基因可能与Pm52不同。石U09-4366、XR4429、衡10-5039和农大3486苗期和成株期都表现感病,不含Pm52基因。这些品种的成株期抗性反应与苗期的抗性反应一致。本研究的结果有利于良星99的抗白粉病基因Pm52在育种和生产上的有效利用。