Lu Jiangjie, Luo Meifang, Wang Li, Li Kunpeng, Yu Yongyi, Yang Weifei, Gong Pichang, Gao Huihui, Li Qiaoru, Zhao Jing, Wu Lanfeng, Zhang Mingshu, Liu Xueyang, Zhang Xuemei, Zhang Xian, Kang Jieyu, Yu Tongyuan, Li Zhimin, Jiao Yuannian, Wang Huizhong, He Chaoying
State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, 100093, Xiangshan, Beijing, China.
Zhejiang Provincial Key Laboratory for Genetic Improvement and Quality Control of Medicinal Plants, College of Life and Environmental Science, Hangzhou Normal University, 310036, Hangzhou, China.
Hortic Res. 2021 Nov 18;8(1):244. doi: 10.1038/s41438-021-00705-w.
The fruits of Physalis (Solanaceae) have a unique structure, a lantern-like fruiting calyx known as inflated calyx syndrome (ICS) or the Chinese lantern, and are rich in steroid-related compounds. However, the genetic variations underlying the origin of these characteristic traits and diversity in Physalis remain largely unknown. Here, we present a high-quality chromosome-level reference genome assembly of Physalis floridana (~1.40 Gb in size) with a contig N50 of ~4.87 Mb. Through evolutionary genomics and experimental approaches, we found that the loss of the SEP-like MADS-box gene MBP21 subclade is likely a key mutation that, together with the previously revealed mutation affecting floral MPF2 expression, might have contributed to the origination of ICS in Physaleae, suggesting that the origination of a morphological novelty may have resulted from an evolutionary scenario in which one mutation compensated for another deleterious mutation. Moreover, the significant expansion of squalene epoxidase genes is potentially associated with the natural variation of steroid-related compounds in Physalis fruits. The results reveal the importance of gene gains (duplication) and/or subsequent losses as genetic bases of the evolution of distinct fruit traits, and the data serve as a valuable resource for the evolutionary genetics and breeding of solanaceous crops.
酸浆属（茄科）植物的果实具有独特的结构，即灯笼状的宿存花萼，称为膨大花萼综合征（ICS）或中国灯笼，并且富含甾体类化合物。然而，酸浆属中这些特征性状起源和多样性背后的遗传变异仍 largely 未知。在此，我们展示了弗罗里达酸浆（大小约为 1.40 Gb）的高质量染色体水平参考基因组组装，其重叠群 N50 约为 4.87 Mb。通过进化基因组学和实验方法，我们发现 SEP 样 MADS 盒基因 MBP21 亚分支的缺失可能是一个关键突变，该突变与先前揭示的影响花 MPF2 表达的突变一起，可能促成了酸浆族中 ICS 的起源，这表明一种形态新奇性的起源可能源于一种进化情景，即一个突变补偿了另一个有害突变。此外，角鲨烯环氧酶基因的显著扩增可能与酸浆属果实中甾体类化合物的自然变异有关。这些结果揭示了基因获得（复制）和/或随后的丢失作为独特果实性状进化的遗传基础的重要性，并且这些数据为茄科作物进化遗传学和育种提供了宝贵资源。
