Chromosome‐level genome of Camellia lanceoleosa provides a valuable resource for understanding genome evolution and self‐incompatibility

作者：Wenfang Gong, Shixin Xiao, Linkai Wang, Zhenyang Liao, Yihong Chang, Wenjuan Mo, Guanxing Hu, Wenying Li, Guang Zhao, Huaguo Zhu, Xiaoming Hu, Ke Ji, Xiaofeng Xiang, Qiling Song, Deyi Yuan, Shuangxia Jin, Lin Zhang · 发表于：The Plant Journal · 年份：2022 · DOI：10.1111/tpj.15739 · 被引用次数：87 · 研究领域：Plant Reproductive Biology、Chromosomal and Genetic Variations、Plant Molecular Biology Research

The section Oleifera (Theaceae) has attracted attention for the high levels of unsaturated fatty acids found in its seeds. Here, we report the chromosome-scale genome of the sect. Oleifera using diploid wild Camellia lanceoleosa with a final size of 3.00 Gb and an N50 scaffold size of 186.43 Mb. Repetitive sequences accounted for 80.63% and were distributed unevenly across the genome. Camellia lanceoleosa underwent a whole-genome duplication event approximately 65 million years ago (65 Mya), prior to the divergence of C. lanceoleosa and Camellia sinensis (approx. 6-7 Mya). Syntenic comparisons of these two species elucidated the genomic rearrangement, appearing to be driven in part by the activity of transposable elements. The expanded and positively selected genes in C. lanceoleosa were significantly enriched in oil biosynthesis, and the expansion of homomeric acetyl-coenzyme A carboxylase (ACCase) genes and the seed-biased expression of genes encoding heteromeric ACCase, diacylglycerol acyltransferase, glyceraldehyde-3-phosphate dehydrogenase and stearoyl-ACP desaturase could be of primary importance for the high oil and oleic acid content found in C. lanceoleosa. Theanine and catechins were present in the leaves of C. lanceoleosa. However, caffeine can not be dectected in the leaves but was abundant in the seeds and roots. The functional and transcriptional divergence of genes encoding SAM-dependent N-methyltransferases may be associated with caffeine accumulation and dist...