scholarly journals Circadian control of ORE1 by PRR9 positively regulates leaf senescence in Arabidopsis

2018 ◽  
Vol 115 (33) ◽  
pp. 8448-8453 ◽  
Author(s):  
Hyunmin Kim ◽  
Hyo Jung Kim ◽  
Quy Thi Vu ◽  
Sukjoon Jung ◽  
C. Robertson McClung ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Leaf Senescence ◽  
Posttranscriptional Regulation ◽  
Clock Genes ◽  
Response Regulator ◽  
Early Flowering ◽  
Physiological Alterations ◽  
Circadian Control ◽  
Age Dependent ◽  
Pseudo Response Regulator

The circadian clock coordinates the daily cyclic rhythm of numerous biological processes by regulating a large portion of the transcriptome. In animals, the circadian clock is involved in aging and senescence, and circadian disruption by mutations in clock genes frequently accelerates aging. Conversely, aging alters circadian rhythmicity, which causes age-associated physiological alterations. However, interactions between the circadian clock and aging have been rarely studied in plants. Here, we investigated potential roles for the circadian clock in the regulation of leaf senescence in plants. Members of the evening complex in Arabidopsis circadian clock, EARLY FLOWERING 3 (ELF3), EARLY FLOWERING 4 (ELF4), and LUX ARRHYTHMO (LUX), as well as the morning component PSEUDO-RESPONSE REGULATOR 9 (PRR9), affect both age-dependent and dark-induced leaf senescence. The circadian clock regulates the expression of several senescence-related transcription factors. In particular, PRR9 binds directly to the promoter of the positive aging regulator ORESARA1 (ORE1) gene to promote its expression. PRR9 also represses miR164, a posttranscriptional repressor of ORE1. Consistently, genetic analysis revealed that delayed leaf senescence of a prr9 mutant was rescued by ORE1 overexpression. Thus, PRR9, a core circadian component, is a key regulator of leaf senescence via positive regulation of ORE1 through a feed-forward pathway involving posttranscriptional regulation by miR164 and direct transcriptional regulation. Our results indicate that, in plants, the circadian clock and leaf senescence are intimately interwoven as are the clock and aging in animals.

scholarly journals Identification and characterization of a circadian clock-associated pseudo-response regulator 7 gene from trifoliate orange

2020 ◽  
Vol 48 (1) ◽  
pp. 128-139
Author(s):  
Yu-E DING ◽  
Wenkai HUANG ◽  
Bo SHU ◽  
Ying-Ning ZOU ◽  
Qiang-Sheng WU ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Response Regulator ◽  
Poncirus Trifoliata ◽  
Pcr Analysis ◽  
Trifoliate Orange ◽  
Drought Treatment ◽  
Reading Frame ◽  
Rhythmic Expression ◽  
Pseudo Response Regulator ◽  
Main Component

Circadian clock is usually involved in many physiological processes of plants, including responses to abiotic stress, whilst pseudo-response regulator 7 (PRR7) gene is the main component of the circadian clock. In this study, the cDNA of the PRR7 gene was obtained from trifoliate orange (Poncirus trifoliata). Based on the sequence analysis, the PtPRR7 gene had an open reading frame of 2343 bp, encoded 780 amino acids, and contained proteins of the REC and CCT domains. Subcellular localization indicated that PtPRR7 was mainly localized in the nucleus and a small amount of cytoplasm. qRT-PCR analysis revealed the highest expression level of PtPRR7 in roots than in both shoots and leaves. The PtPRR7 gene during 24 hours of soil water deficit exhibited a circadian rhythmic expression pattern: the expression peak at 9:00 am in leaves and at 21:00 pm in roots. Drought treatment affected PtPRR7 gene expression. Such data provide important references for understanding the characteristics of PtPRR7 gene in citrus plants.

scholarly journals Transcript Profiling of an Arabidopsis PSEUDO RESPONSE REGULATOR Arrhythmic Triple Mutant Reveals a Role for the Circadian Clock in Cold Stress Response

2009 ◽  
Vol 50 (3) ◽  
pp. 447-462 ◽  
Author(s):  
Norihito Nakamichi ◽  
Miyako Kusano ◽  
Atsushi Fukushima ◽  
Masanori Kita ◽  
Shogo Ito ◽  
...  
Keyword(s):  
Stress Response ◽  
Cold Stress ◽  
Circadian Clock ◽  
Response Regulator ◽  
Transcript Profiling ◽  
Triple Mutant ◽  
Pseudo Response Regulator

scholarly journals GhLUX1 and GhELF3 Are Two Components of the Circadian Clock That Regulate Flowering Time of Gossypium hirsutum

2021 ◽  
Vol 12 ◽  
Author(s):  
Pengbo Hao ◽  
Aimin Wu ◽  
Pengyun Chen ◽  
Hantao Wang ◽  
Liang Ma ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Flowering Time ◽  
Clock Genes ◽  
Early Flowering ◽  
Rhythmic Expression ◽  
Photoperiodic Flowering ◽  
Early Maturing ◽  
Circadian Clock Genes ◽  
Delayed Flowering ◽  
Physicochemical And Structural Properties

Photoperiod is an important external factor that regulates flowering time, the core mechanism of which lies in the circadian clock-controlled expression of FLOWERING LOCUS T (FT) and its upstream regulators. However, the roles of the circadian clock in regulating cotton flowering time are largely unknown. In this study, we cloned two circadian clock genes in cotton, GhLUX1 and GhELF3. The physicochemical and structural properties of their putative proteins could satisfy the prerequisites for the interaction between them, which was proved by yeast two-hybrid (Y2H) and Bimolecular Fluorescent Complimentary (BiFC) assays. Phylogenetic analysis of LUXs and ELF3s indicated that the origin of LUXs was earlier than that of ELF3s, but ELF3s were more divergent and might perform more diverse functions. GhLUX1, GhELF3, GhCOL1, and GhFT exhibited rhythmic expression and were differentially expressed in the early flowering and late-flowering cotton varieties under different photoperiod conditions. Both overexpression of GhLUX1 and overexpression of GhELF3 in Arabidopsis delayed flowering probably by changing the oscillation phases and amplitudes of the key genes in the photoperiodic flowering pathway. Both silencing of GhLUX1 and silencing of GhELF3 in cotton increased the expression of GhCOL1 and GhFT and resulted in early flowering. In summary, the circadian clock genes were involved in regulating cotton flowering time and could be the candidate targets for breeding early maturing cotton varieties.

scholarly journals GUN4 Affects the Circadian Clock and Seedlings Adaptation to Changing Light Conditions

2021 ◽  
Vol 23 (1) ◽  
pp. 194
Author(s):  
Tao Li ◽  
Rui Wu ◽  
Zhixin Liu ◽  
Jiajing Wang ◽  
Chenxi Guo ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Clock Genes ◽  
Response Regulator ◽  
Signal Recognition Particle ◽  
Biological Clock ◽  
Chlorophyll Synthesis ◽  
Light Conditions ◽  
Strong Light ◽  
Expression Of Genes ◽  
Changing Light

The chloroplast is a key organelle for photosynthesis and perceiving environmental information. GENOME UNCOUPLED 4 (GUN4) has been shown to be required for the regulation of both chlorophyll synthesis, reactive oxygen species (ROS) homeostasis and plastid retrograde signaling. In this study, we found that growth of the gun4 mutant was significantly improved under medium strong light (200 μmol photons m−2s−1) compared to normal light (100 μmol photons m−2s−1), in marked contrast to wild-type (WT). Further analysis revealed that GUN4 interacts with SIGNAL RECOGNITION PARTICLE 54 KDA SUBUNIT (SRP43) and SRP54. RNA-seq analysis indicated that the expression of genes for light signaling and the circadian clock is altered in gun4 compared with (WT). qPCR analysis confirmed that the expression of the clock genes CLOCK-RELATED 1 (CCA1), LATE ELONGATION HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO RESPONSE REGULATOR 7 (PRR7) is significantly changed in the gun4 and srp54 mutants under normal and medium strong light conditions. These results suggest that GUN4 may coordinate the adaptation of plants to changing light conditions by regulating the biological clock, although it is not clear whether the effect is direct or indirect.

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