Effects of light spectrum on the morphophysiology and gene expression of lateral branching in Pepino (Solanum muricatum)

Cheng Si; Shipeng Yang; Xiangyun Lou; Guangnan Zhang; Qiwen Zhong

doi:10.3389/fpls.2022.1012086

Effects of light spectrum on the morphophysiology and gene expression of lateral branching in Pepino (Solanum muricatum)

Front Plant Sci. 2022 Sep 23:13:1012086. doi: 10.3389/fpls.2022.1012086. eCollection 2022.

Authors

Cheng Si^{1

2}, Shipeng Yang^{1

3}, Xiangyun Lou¹, Guangnan Zhang¹, Qiwen Zhong^{1

4}

Affiliations

¹ Qinghai Key Laboratory of Vegetable Genetics and Physiology, Agriculture and Forestry Sciences Institute of Qinghai University, Xining, China.
² Qinghai University, Xining, China.
³ College of Life Sciences, Northwest A&F University, Xining, China.
⁴ Laboratory for Research and Utilization of Germplasm Resources in Qinghai Tibet Plateau, Xi'an, China.

Abstract

In the present study, we determined the morphological and physiological indicators of Pepino to elucidate its lateral branching responses to different light qualities using a full-spectrum lamp (F) as the control and eight different light ratios using blue light (B) and red light (R). In addition, correlation analysis revealed that the gene expression patterns correlated with lateral branching under various light treatments. Compared with the F treatment, the R treatment increased the plant height and inhibited the elongation of lateral branches, in contrast with the B treatment. The number of lateral branches did not change significantly under different light quality treatments. Moreover, correlation analysis showed that the ratio of blue light was significantly positively correlated with the length of lateral branches and significantly negatively correlated with plant height, aboveground dry weight, and other indicators. We conducted transcriptome sequencing of the sites of lateral branching at three periods under different light quality treatments. The gene related to photodynamic response, cryptochrome (CRY), was the most highly expressed under B treatment, negatively regulated lateral branch length, and positively correlated with plant height. Branched 1, a lateral branch regulation gene, was upregulated under R treatment and inhibited branching. Overall, the red light facilitated internode elongation, leaf area expansion, plant dry weight increase, and inhibition of lateral branching. Soluble sugar content increased, and the lateral branches elongated under blue light. Different light qualities regulated lateral branching by mediating different pathways involving strigolactones and CRY. Our findings laid a foundation for further clarifying the response mechanism of Pepino seedlings to light and provided a theoretical reference for elucidating the regulation of different light qualities on the lateral branching of Pepino.

Keywords: LED lamp; Pepino; gene expression; lateral branch; photomorphogenesis.