Chen Chen2#, Zilue Zheng2#, Dandan Wu2, 5, Lu Tan2, Cairong Yang4, Songqing Liu4, Jiale Lu1, 5, Xing Fan2, 5, Lina Sha2, 5, Houyang Kang2, 5, Yi Wang2, 5, Yonghong Zhou2, 5, Changbing Zhang3*, Haiqin Zhang1, 5*
1 College of Grassland Science and Technology, Sichuan Agricultural University, Chengdu 611130, Sichuan, China;
2 Triticeae Research Institute, Sichuan Agricultural University, Chengdu 611130, Sichuan, China;
3 Sichuan Academy of Grassland Science, Chengdu 610000, Sichuan, China;
4 College of Chemistry and Life Sciences, Chengdu Normal University, Chengdu 611130, Sichuan, China;
5State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China,Sichuan Agricultural University, Chengdu 611130, Sichuan, China .
*Corresponding author. E-mail:haiqinzhang@163.com (HQ. Zhang), c.b.zhang@126. com(CB. Zhang)
Abstract Hybridization is an important part of species evolution. The hybrid progeny population had rich genetic and phenotypic variation, which made the boundaries between them and their parents blurred and difficult to distinguish. There was little research on the origin of natural hybrids of Triticeae. In this study, we found a large number of putative hybrids of Roegneria in West Sichuan Plateau, China. The hybrid plants showed strong heterosis in plant height, tiller number and floret number. Morphologically, the putative hybrids showed intermediate of Roegneria stricta Keng and Roegneriaturczaninovii (Drob.) Nevski. Hybrids had 28 chromosomes corresponding to that ofR. stricta and R. tu rczaninovii (2n=4x=28). Meiotic pairing in hybrids were less regular than those of R. stricta andR. turczaninovii . GISH analysis showed that the hybrid plants had the same genome as that of R. stricta and R. turczaninovii(StY ). Phylogenetic analysis based on the single copy nuclear gene DMC 1 and chloroplast gene rps 16 showed the plants were closely related to R . stricta and R. turczaninovii. This study indicated that the plants were hybrids ofR. strictaandR. turczaninovi i. The results provided data for the utilization of hybrid. This study provided a case study of natural hybrids.
KEYWORDS Natural hybrids, GISH, phylogenetic analysis, Roegneria , genome, meiotic pairing.
Cover letter
Dear editor,
The submitted is the following manuscript for your consideration to Ecology and Evolution: “Molecular cytogenetic characterization of natural hybrids of Roegneria stricta andRoegneria turczaninovii (Triticeae: Poaceae) ”, by Chen Chen, Zi-Lue Zheng, Dan-Dan Wu, Tan Lu, Cai-Rong Yang, Song-Qing Liu, Jia-Le Lu, Yong-Hong Zhou, Chang-Bing Zhang, Hai-Qin Zhang.
In the present study, to explore the origin and formation mechanism of natural hybrids, we performed morphological analysis, Karyotype analysis, chromosome pairing analysis, genomic in situhybridization and phylogenetic analyses. The results confirmed that natural hybrids showed strong heterosis in plant height, tiller number and floret number. Morphologically, the hybrids showed intermediate ofRoegneria stricta Keng and Roegneria turczaninovii (Drob.) Nevski. Meiotic pairing in hybrids were less regular than those ofR. stricta and R. turczaninovii . GISH analysis showed that the hybrid plants had the same genome as that of R. stricta andR. turczaninovii (StY ). Phylogenetic analysis based on the single copy nuclear gene DMC 1 and chloroplast generps 16 showed the plants were closely related to R. strictaand R. turczaninovii . This study indicated that the plants were hybrids of R. stricta and R. turczaninovii .
The work described has not been submitted elsewhere for publication, in whole or in part, and all authors listed have approved the manuscript that enclosed.
We hope that you will kindly consider this submission for publication.
If you have any questions, please contact me freely.
Sincerely,
Haiqin Zhang
College of Grassland Science and Technology,
Sichuan Agricultural University,
Wenjiang 611130,
China
haiqinzhang@163.com; Tel: +86 13550042478