# Identification and Expression Characteristics of the Cryptochrome Gene Family in Chimonobambusa sichuanensis

## TL;DR

This paper identifies and analyzes the Cryptochrome gene family in Chimonobambusa sichuanensis to understand how blue light affects its color change.

## Contribution

The study identifies four Cryptochrome genes in Chimonobambusa sichuanensis and their expression under varying light and temperature conditions.

## Key findings

- Four CsCRY genes (CsCRY1a, CsCRY1b, CsCRY2, CsCRY3) were identified in Chimonobambusa sichuanensis.
- CsCRY genes showed up-regulated expression under blue light and low-temperature stress.
- CsCRY2 expression was highest under blue light, while CsCRY1a and CsCRY1b were higher in mixed red and blue light.

## Abstract

Cryptochrome is an important class of blue-light receptors involved in various physiological activities such as photomorphogenesis and abiotic stress regulation in plants. In order to investigate the molecular mechanism of blue-light-induced color change in Chimonobambusa sichuanensis, we screened and cloned the gene encoding the blue-light receptor Cryptochrome. In order to investigate the molecular mechanism of blue-light-induced color change in Chimonobambusa sichuanensis, we screened and cloned the gene encoding the blue-light receptor Cryptochrome in Ch.sichuanensis, and analyzed the expression characteristics of the Cryptochrome gene in Ch.sichuanensis under different light intensities, light quality, and temperatures by qRT-PCR. Through homologous cloning, a total of four CsCRY genes were obtained in the Ch.sichuanensis genome, namely, CsCRY1a, CsCRY1b, CsCRY2, and CsCRY3. Structural domain analyses of the encoded proteins of the four genes revealed that all CsCRYs proteins had the typical photoreceptor structural domain, PRK (protein kinase C-related kinase). Phylogenetic tree analyses revealed that the four genes CsCRY1a, CsCRY1b, CsCRY2, and CsCRY3 could be categorized into three subfamilies, with CsCRY1a and CsCRY1b clustered in subfamily I, CsCRY2 classified in subfamily II, and CsCRY3 belonging to subfamily III. All CsCRYs proteins lacked signal peptides and the instability index was higher than 40, among which the isoelectric points of CsCRY1a, CsCRY1b, and CsCRY2 were around five. qRT-PCR analysis revealed that the expression of all four CsCRYs genes was up-regulated at 75 µmol·m−2·s−1 blue-light illumination for 4 h. In addition, under treatments of different light quality, the expression of CsCRY2 genes was significantly higher under blue light than under red light and a mixture of red light and blue light with a light intensity of 1:1; the expression of CsCRY1a and CsCSY1b was significantly higher in the mixed light of red and blue light than in the single light treatment, while under different temperature gradients, CsCRYs genes were highly expressed under low-temperature stress at −5 °C and 0 °C. This study provides a basis for further research on blue-light-induced color change in Ch.sichuanensis and expands the scope of Cryptochrome gene research.