Genome-Wide Identification, Expression Analysis and Functional Study of CCT Gene Family in Medicago truncatula

Abstract

The control of flowering time has an important impact on biomass and the environmental adaption of legumes. The CCT (CO, COL and TOC1) gene family was elucidated to participate in the molecular regulation of flowering in plants. We identified 36 CCT genes in the M. truncatula genome and they were classified into three distinct subfamilies, PRR (7), COL (11) and CMF (18). Synteny and phylogenetic analyses revealed that CCT genes occurred before the differentiation of monocot and dicot, and CCT orthologous genes might have diversified among plants. The diverse spatial-temporal expression profiles indicated that MtCCT genes could be key regulators in flowering time, as well as in the development of seeds and nodules in M. truncatula. Notably, 22 MtCCT genes with typical circadian rhythmic variations suggested their different responses to light. The response to various hormones of MtCCT genes demonstrated that they participate in plant growth and development via varied hormones dependent pathways. Moreover, six MtCCT genes were dramatically induced by salinity and dehydration treatments, illustrating their vital roles in the prevention of abiotic injury. Collectively, our study provides valuable information for the in-depth investigation of the molecular mechanism of flowering time in M. truncatula, and it also provides candidate genes for alfalfa molecular breeding with ideal flowering time.

The Papain-like Cysteine Protease HpXBCP3 from Haematococcus pluvialis Involved in the Regulation of Growth, Salt Stress Tolerance and Chlorophyll Synthesis in Microalgae

“…It was reported that over-expression of TOC1, a key component of the circadian clocks belonging to CCT family, significantly reduced the drought tolerance in Arabidopsis [24]. Moreover, the biorhythm-related CCT family genes in Medicago truncatula responded to NaCl stress [25]. In plants, WD40 proteins were involved in plant development, response to stress and other physiological activities [26,27].…”

Circadian Rhythms in Legumes: What Do We Know and What Else Should We Explore?

“…Recently, Ma et al [ 86 ] reported a comprehensive analysis of 36 circadian-related genes, namely those containing the CCT domain. The CCT ( CONSTANTS-CONSTANS LIKE-TIMING OF CAB 1 ) genes have been previously implicated in flowering time regulation and biomass accumulation [ 87 ].…”

“…The CCT ( CONSTANTS-CONSTANS LIKE-TIMING OF CAB 1 ) genes have been previously implicated in flowering time regulation and biomass accumulation [ 87 ]. Gene clustering analysis for barrel medic associated the CCT genes with flowering time regulation, abiotic stress response, and regulation of growth and development [ 86 ]. A recent study revealed that the LHY ( LATE ELONGATED HYPOCOTYLS ) gene also plays an essential role in the regulation of the endogenous biological clock in barrel medic [ 48 ].…”

Genome-Wide Analysis of CCT Transcript Factors to Identify Genes Contributing to Photoperiodic Flowering in Oryza rufipogon

“…Our previous investigation suggested that natural populations of O. rufipogon exhibited clinal variation in flowering time from north to south within its range in China ( Gao et al, 2000 ). The CCT TFs have been identified and functionally elucidated in several crop species, such as rice ( Zhang et al, 2017 ), maize ( Huang et al, 2018 ), wheat ( Yan et al, 2004 ), barley ( Turner et al, 2005 ), and Medicago truncatula ( Ma et al, 2020 ). However, functional roles of CCT TFs have not been elucidated in their wild progenitors, such as O. rufipogon in this study.…”