State Key Laboratory of Cotton Biology, Henan Key Laboratory of Plant Stress Biology, School of Life Sciences, Bioinformatics Center, School of Computer and Information Engineering, Henan University, Kaifeng, China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, China.
Plant Biotechnol J. 2020 Mar;18(3):814-828. doi: 10.1111/pbi.13249. Epub 2019 Sep 13.
The diploid wild cotton species Gossypium australe possesses excellent traits including resistance to disease and delayed gland morphogenesis, and has been successfully used for distant breeding programmes to incorporate disease resistance traits into domesticated cotton. Here, we sequenced the G. australe genome by integrating PacBio, Illumina short read, BioNano (DLS) and Hi-C technologies, and acquired a high-quality reference genome with a contig N50 of 1.83 Mb and a scaffold N50 of 143.60 Mb. We found that 73.5% of the G. australe genome is composed of various repeat sequences, differing from those of G. arboreum (85.39%), G. hirsutum (69.86%) and G. barbadense (69.83%). The G. australe genome showed closer collinear relationships with the genome of G. arboreum than G. raimondii and has undergone less extensive genome reorganization than the G. arboreum genome. Selection signature and transcriptomics analyses implicated multiple genes in disease resistance responses, including GauCCD7 and GauCBP1, and experiments revealed induction of both genes by Verticillium dahliae and by the plant hormones strigolactone (GR24), salicylic acid (SA) and methyl jasmonate (MeJA). Experiments using a Verticillium-resistant domesticated G. barbadense cultivar confirmed that knockdown of the homologues of these genes caused a significant reduction in resistance against Verticillium dahliae. Moreover, knockdown of a newly identified gland-associated gene GauGRAS1 caused a glandless phenotype in partial tissues using G. australe. The G. australe genome represents a valuable resource for cotton research and distant relative breeding as well as for understanding the evolutionary history of crop genomes.
二倍体野生棉种 Gossypium australe 具有优良的特性，包括对疾病的抗性和腺体形态发生的延迟，并且已经成功地用于远缘杂交计划，将疾病抗性特性纳入到驯化棉中。在这里，我们通过整合 PacBio、Illumina 短读、BioNano（DLS）和 Hi-C 技术对 G. australe 基因组进行测序，获得了一个高质量的参考基因组，其 contig N50 为 1.83 Mb，scaffold N50 为 143.60 Mb。我们发现，73.5%的 G. australe 基因组由各种重复序列组成，与 G. arboreum（85.39%）、G. hirsutum（69.86%）和 G. barbadense（69.83%）不同。G. australe 基因组与 G. arboreum 基因组的共线性关系比 G. raimondii 更密切，并且基因组重组程度比 G. arboreum 基因组小。选择标记和转录组学分析表明，多个基因参与了疾病抗性反应，包括 GauCCD7 和 GauCBP1，实验表明这两个基因都被Verticillium dahliae 和植物激素独脚金内酯（GR24）、水杨酸（SA）和茉莉酸甲酯（MeJA）诱导。使用抗 Verticillium 的驯化 G. barbadense 品种进行的实验证实，这些基因的同源物的敲低导致对 Verticillium dahliae 的抗性显著降低。此外，使用 G. australe 敲低新鉴定的腺体相关基因 GauGRAS1 会导致部分组织出现无腺体表型。G. australe 基因组是棉花研究和远缘杂交以及理解作物基因组进化历史的宝贵资源。
