Photosynthetic Efficiency and Glyco-Metabolism Changes in Artificial Triploid Loquats Contribute to Heterosis Manifestation

Lingli Wang; Meiyan Tu; Jing Li; Shuxia Sun; Haiyan Song; Zihong Xu; Dong Chen; Guolu Liang

doi:10.3390/ijms231911337

Photosynthetic Efficiency and Glyco-Metabolism Changes in Artificial Triploid Loquats Contribute to Heterosis Manifestation

Int J Mol Sci. 2022 Sep 26;23(19):11337. doi: 10.3390/ijms231911337.

Authors

Lingli Wang¹, Meiyan Tu¹, Jing Li¹, Shuxia Sun¹, Haiyan Song¹, Zihong Xu¹, Dong Chen¹, Guolu Liang²

Affiliations

¹ Horticultural Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China.
² College of Horticulture and Landscape Architecture, Southwest University, Tiansheng Road 2, Chongqing 400715, China.

Abstract

Previous studies indicated that extensive genetic variations could be generated due to polyploidy, which is considered to be closely associated with the manifestation of polyploid heterosis. Our previous studies confirmed that triploid loquats demonstrated significant heterosis, other than the ploidy effect, but the underlying mechanisms are largely unknown. This study aimed to overcome the narrow genetic distance of loquats, increase the genetic variation level of triploid loquats, and systematically illuminate the heterosis mechanisms of triploid loquats derived from two cross combinations. Here, inter-simple sequence repeats (ISSRs) and simple sequence repeats (SSRs) were adopted for evaluating the genetic diversity, and transcriptome sequencing (RNA-Seq) was performed to investigate gene expression as well as pathway changes in the triploids. We found that extensive genetic variations were produced during the formation of triploid loquats. The polymorphism ratios of ISSRs and SSRs were 43.75% and 19.32%, respectively, and almost all their markers had a PIC value higher than 0.5, suggesting that both ISSRs and SSRs could work well in loquat assisted breeding. Furthermore, our results revealed that by broadening the genetic distance between the parents, genetic variations in triploids could be promoted. Additionally, RNA-Seq results suggested that numerous genes differentially expressed between the triploids and parents were screened out. Moreover, KEGG analyses revealed that "photosynthetic efficiency" and "glyco-metabolism" were significantly changed in triploid loquats compared with the parents, which was consistent with the results of physiological indicator analyses, leaf micro-structure observations, and qRT-PCR validation. Collectively, our results suggested that extensive genetic variations occurred in the triploids and that the changes in the "photosynthetic efficiency" as well as "glyco-metabolism" of triploids might have further resulted in heterosis manifestation in the triploid loquats.

Keywords: glyco-metabolism; heterosis; photosynthetic efficiency; transcriptome sequencing; triploid loquat.

MeSH terms

Eriobotrya* / genetics
Hybrid Vigor / genetics
Plant Breeding
Ploidies
Triploidy*

Grants and funding

This research was funded by Studies on the Variety Screenings and Propagation Techniques of Apple, Peach and Loquat [2021YFD1600801], Sichuan Youth Science and technology Innovation Research Team for Characteristic Fruit project [2020JDTD0032] and Breakthrough in Fruit Tree Breeding Material, Method Innovation and New Variety Breeding project [2021YFYZ0023]. And the APC was funded by [2021YFD1600801].