Genome-wide analysis of auxin transport genes identifies the hormone responsive patterns associated with leafy head formation in Chinese cabbage

Abstract

Auxin resistant 1/like aux1 (AUX/LAX), pin-formed (PIN) and ATP binding cassette subfamily B (ABCB/MDR/PGP) are three families of auxin transport genes. The development-related functions of the influx and efflux carriers have been well studied and characterized in model plants. However, there is scant information regarding the functions of auxin genes in Chinese cabbage and the responses of exogenous polar auxin transport inhibitors (PATIs). We conducted a whole-genome annotation and a bioinformatics analysis of BrAUX/LAX, BrPIN, and BrPGP genes in Chinese cabbage. By analyzing the expression patterns at several developmental stages in the formation of heading leaves, we found that most auxin-associate genes were expressed throughout the entire process of leafy head formation, suggesting that these genes played important roles in the development of heads. UPLC was used to detect the distinct and uneven distribution of auxin in various segments of the leafy head and in response to PATI treatment, indicated that the formation of the leafy head depends on polar auxin transport and the uneven distribution of auxin in leaves. This study provides new insight into auxin polar transporters and the possible roles of the BrLAX, BrPIN and BrPGP genes in leafy head formation in Chinese cabbage.

Conjunctive Analyses of BSA-Seq and BSR-Seq to Reveal the Molecular Pathway of Leafy Head Formation in Chinese Cabbage

“…In this study, GARP transcription factor family gene BrKAN2 (Bra039528), a key regulator of leaf abaxial polarity, was identified by the association analysis of BSA-Seq analysis. It has been proven that the leafy head formation in Chinese cabbage can be affected by the uneven distribution of auxin in heading leaves [4].…”

“…However, the molecular mechanism of leafy head formation in Chinese cabbage remains elusive. The leafy head development of Chinese cabbage is affected by diversity factors, such as phytohormones' uneven distribution [4], low temperature induction [5] and leafy shape [6].…”

“…Previously, transgenic Chinese cabbage with an auxin biosynthesis gene showed more rapid and larger size head formation [2]. Gao et al (2017) reported that influx auxin carrier BrAUX/LAX and efflux auxin carrier BrPIN and BrPGP played critical roles in Chinese cabbage leafy head formation by regulating auxin uneven distribution [4].…”

The auxin influx carrier, OsAUX3, regulates rice root development and responses to aluminium stress

“…In Chinese cabbage ( Brassica rapa L. ssp. pekinensis ), it is suggested that BrLAX genes may be involved in PAT during leafy head development (Gao et al, ). In rice, there are five members of the AUX1/LAX family (Shen et al, ).…”

Morphological and genetic characterization of the leafy head of Chinese cabbage (Brassica rapa)

“…Chinese cabbage with its leafy head is one of the most important vegetable crops in China. The leafy head ensures high yields, allows for nutrient storage and tolerance against both biotic and abiotic stresses (Tao et al, 2015;Gao et al, 2017). The Chinese cabbage leafy head is composed of a number of tightly packed heading leaves.…”