Study on Gene Differential Expression in Tetraploid Populus Leaves

Ying Zhang,Xiangyang Kang,Yongyu Ren

doi:10.3390/f11111233

Abstract

Polyploids exhibit different phenotypes compared to those of diploids in plants, and the important role of polyploids in tree breeding has been widely recognized. The transcriptomes detected by RNA-seq in the Populus triploid by doubling the chromosomes of the female gamete, in the triploid by doubling the chromosomes of somatic cells and the diploid with the parent were compared to reveal the patterns of gene expression of tetraploid leaves and their influence on growth. The results showed that the high expression of GATA and PORA in tetraploid leaves was the reason for the higher chlorophyll content in the leaves than in diploid and triploid leaves. The 11-day-old tetraploid leaves began to enter the aging stage. Compared with that in the diploid, GRF was significantly upregulated, while the amylase genes were downregulated. Compared with those in the triploid, 3 STN7 genes that regulate photosynthetic genes and PGSIP genes which are related to starch synthesis, were significantly downregulated in the tetraploid, and the auxin receptor protein TIR1 was also significantly downregulated. In the tetraploid, auxin-regulating genes such as GH3 and AUX/IAA as well as genes involved in the regulation of leaf senescence, SAG genes and SRG genes were significantly up-regulated, resulting in a decrease in the auxin content. In senescent leaves, CHLD, CHLI1, and CHLM in the early stage of chlorophyll synthesis all began to downregulate their expressions, leading to the downregulation of LHC genes and a decrease in their photosynthetic efficiency, which led to the downregulation of carbon fixation-related genes such as SS genes, thus affecting carbon synthesis and fixation. This finally led to the slow growth of tetraploid plants. These data represent the transcriptome characteristics of tetraploid, and they can be used as a resource for further research on polyploids and provide a reference for further understanding of the function of polyploid vegetative growth-related genes.

Highlights

IntroductionPolyploid plants usually have strong stems, large fruits, and rich metabolites [1,2,3]
Compared with diploid plants, polyploid plants usually have strong stems, large fruits, and rich metabolites [1,2,3]
The tissue culture seedlings with the same culture time and same growth conditions were transplanted to the greenhouse, and even the tetraploid grew slightly stronger than the diploid plants before transplantation

Summary

Introduction

Polyploid plants usually have strong stems, large fruits, and rich metabolites [1,2,3]. In 1935, Nilsson-Ehle discovered the natural triploid of giant European aspen [4]. The wood increment of artificial triploid poplar was 2−3 times higher than that of common poplar, and the growth rate of artificial triploid poplar had reached the growth level of fast-growing black poplar [5]. The Medicago sativa tetraploid is taller than the diploid [6]. The Arabidopsis thaliana tetraploid has larger leaves than diploid, and tetraploid is more robust [7,8].

Methods

Results

Conclusion