马铃薯细胞嵌合体引起生物量增加的成因与发生机制研究

多倍体通常导致生长活力增加和生物量提高，对其发生机制有多种假说。细胞嵌合体是基因组加倍不完全的个体，其顶端分生组织的三个细胞层由两种或以上倍性细胞组成。通常细胞嵌合体作为倍性育种过程中的次品被丢弃。申请者前期研究获得多个马铃薯细胞嵌合体和同源四倍体，发现含少量加倍细胞（约30%）的细胞嵌合体比二倍体亲本（Solanum chacoense）和同源四倍体有更强的生物量优势。本项目将利用这些创新性实验材料，结合申请者建立的细胞倍性精确鉴定技术，通过表型性状鉴定、组织结构观察、细胞壁组分、纤维素转化率和转录组分析等方法，1）明确细胞嵌合体哪一细胞层基因组加倍导致强生物量优势；2）了解不同细胞层在生物量增加形成中的作用；3）研究细胞嵌合体的遗传和表型稳定性；4）寻找与生物量增加相关的差异表达基因。项目的开展将增进对多倍化导致生物量增加的成因和机制的认识，为细胞嵌合体在作物育种的利用提供新思路。

Plant polyploidy usually induces increased growth vigor, biomass and adaptability, which has played a key role in plant breeding and crop improvement. While cytochimeras, as a byproduct of ploidy breeding, are intensively avoided and discarded due to theirs incomplete genome doubling. Until now, the mechanism of the increase of biomass caused by polyploidy is not clear. In previous study, we found that potato cytochimera had the most significant growth vigor and biomass than both of the diploid progenitor (Solanum chacoense) and autotetraploids. In this project, using a newly developed technology for precisely identifying the level of ploidy, the applicants will conduct phenotypic identification, tissue dissection, cell wall composition assay, saccharification yield efficiency and transcriptome analyses on these innovative materials. The goals of this project are to: 1) Identify the apical layers with genome duplication leading to the biomass increase in cytochimera. 2) Understand the role of different apical layers in the formation of biomass. 3) Study the genetic and phenotypic stability of the cytochimeras. 4) Find out the differentially expressed genes related to biomass increase. The completion of this project will significantly improve our knowledge about the mechanism of genomic doubling induced growth vigor and will provide a new approach for crop breeding.