scholarly journals SlGRAS4 accelerates fruit ripening by regulating ethylene biosynthesis genes and SlMADS1 in tomato

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yudong Liu ◽  
Yuan Shi ◽  
Deding Su ◽  
Wang Lu ◽  
Zhengguo Li
Keyword(s):  
Transcription Factors ◽  
Stress Responses ◽  
Fruit Ripening ◽  
Tomato Fruit ◽  
Ethylene Biosynthesis ◽  
Negative Regulator ◽  
Carotenoid Content ◽  
Total Carotenoid Content ◽  
Tomato Fruit Ripening ◽  
Transcriptional Regulatory Mechanisms

AbstractGRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses. However, their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear. Here, we demonstrated that SlGRAS4, encoding a transcription factor of the GRAS family, was induced by the tomato ripening process and regulated by ethylene. Overexpression of SlGRAS4 accelerated fruit ripening, increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit. The expression levels of key ethylene biosynthesis genes (SlACS2, SlACS4, SlACO1, and SlACO3) and crucial ripening regulators (RIN and NOR) were increased in SlGRAS4-OE fruit. The negative regulator of tomato fruit ripening, SlMADS1, was repressed in OE fruit. Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit. More obvious phenotypes were observed in OE seedlings after ACC treatment. Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription, and SlGRAS4 can also directly repress SlMADS1 expression. Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner. This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.

scholarly journals Re-evaluation of the nor mutation and the role of the NAC-NOR transcription factor in tomato fruit ripening

2020 ◽  
Vol 71 (12) ◽  
pp. 3560-3574 ◽  
Author(s):  
Ying Gao ◽  
Wei Wei ◽  
Zhongqi Fan ◽  
Xiaodan Zhao ◽  
Yiping Zhang ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Tomato Fruit ◽  
Pectate Lyase ◽  
Ethylene Biosynthesis ◽  
Fruit Softening ◽  
Wild Type ◽  
Gain Of Function ◽  
Carotenoid Accumulation ◽  
Acid Protein ◽  
Tomato Fruit Ripening

Abstract The tomato non-ripening (nor) mutant generates a truncated 186-amino-acid protein (NOR186) and has been demonstrated previously to be a gain-of-function mutant. Here, we provide more evidence to support this view and answer the open question of whether the NAC-NOR gene is important in fruit ripening. Overexpression of NAC-NOR in the nor mutant did not restore the full ripening phenotype. Further analysis showed that the truncated NOR186 protein is located in the nucleus and binds to but does not activate the promoters of 1-aminocyclopropane-1-carboxylic acid synthase2 (SlACS2), geranylgeranyl diphosphate synthase2 (SlGgpps2), and pectate lyase (SlPL), which are involved in ethylene biosynthesis, carotenoid accumulation, and fruit softening, respectively. The activation of the promoters by the wild-type NOR protein can be inhibited by the mutant NOR186 protein. On the other hand, ethylene synthesis, carotenoid accumulation, and fruit softening were significantly inhibited in CR-NOR (CRISPR/Cas9-edited NAC-NOR) fruit compared with the wild-type, but much less severely affected than in the nor mutant, while they were accelerated in OE-NOR (overexpressed NAC-NOR) fruit. These data further indicated that nor is a gain-of-function mutation and NAC-NOR plays a significant role in ripening of wild-type fruit.

scholarly journals Comprehensive Analysis of ABA Effects on Ethylene Biosynthesis and Signaling during Tomato Fruit Ripening

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0154072 ◽  
Author(s):  
Wangshu Mou ◽  
Dongdong Li ◽  
Jianwen Bu ◽  
Yuanyuan Jiang ◽  
Zia Ullah Khan ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Tomato Fruit ◽  
Ethylene Biosynthesis ◽  
Comprehensive Analysis ◽  
Tomato Fruit Ripening ◽  
Ethylene Biosynthesis And Signaling

scholarly journals Tomato fruit ripening factor NOR controls leaf senescence

2018 ◽  
Author(s):  
Xuemin Ma ◽  
Salma Balazadeh ◽  
Bernd Mueller-Roeber
Keyword(s):  
Leaf Senescence ◽  
Stress Responses ◽  
Fruit Ripening ◽  
Higher Plants ◽  
Tomato Fruit ◽  
Leaf Age ◽  
Nac Transcription Factors ◽  
Tomato Fruit Ripening ◽  
Elevated Expression ◽  
Senescence Associated Genes

AbstractNAC transcription factors (TFs) are important regulators of expressional reprogramming during plant development, stress responses and leaf senescence. NAC TFs also play important roles in fruit ripening. In tomato (Solanum lycopersicum), one of the best characterized NAC involved in fruit ripening is NON-RIPENING (NOR) and the non-ripening (nor) mutation has been widely used to extend fruit shelf life in elite varieties. Here, we show that NOR additionally controls leaf senescence. Expression of NOR increases with leaf age, and developmental as well as dark-induced senescence are delayed in the nor mutant, while overexpression of NOR promotes leaf senescence. Genes associated with chlorophyll degradation as well as senescence-associated genes (SAGs) show reduced and elevated expression, respectively, in nor mutants and NOR overexpressors. Overexpression of NOR also stimulates leaf senescence in Arabidopsis thaliana. In tomato, NOR supports senescence by directly and positively regulating the expression of several senescence-associated genes including, besides others, SlSAG15 and SlSAG113, SlSGR1 and SlYLS4. Finally, we find that another senescence control NAC TF, namely SlNAP2, acts upstream of NOR to regulate its expression. Our data support a model whereby NAC TFs have often been recruited by higher plants for both, the control of leaf senescence and fruit ripening.

Gibberellins Play a Role in Regulating Tomato Fruit Ripening

2019 ◽  
Vol 60 (7) ◽  
pp. 1619-1629 ◽  
Author(s):  
Hu Li ◽  
Han Wu ◽  
Qi Qi ◽  
Huihui Li ◽  
Zhifei Li ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Ethylene Production ◽  
Tomato Fruit ◽  
Ethylene Biosynthesis ◽  
Gene Expressions ◽  
Tomato Fruit Ripening ◽  
Early Ripening ◽  
Negative Role ◽  
Regulator Genes ◽  
Prohexadione Calcium

AbstractAlthough exogenous applications of gibberellins (GAs) delay tomato ripening, the regulatory mechanisms of GAs in the process have never been well recognized. Here, we report that the concentration of endogenous GAs is declined before the increase of ethylene production in mature-green to breaker stage fruits. We further demonstrate that reductions in GA levels via overexpression of a GA catabolism gene SlGA2ox1 specifically in fruit tissues lead to early ripening. Consistently, we have also observed that application of a GA biosynthetic inhibitor, prohexadione-calcium, at the mature-green stage accelerates fruit ripening, while exogenous GA3 application delays the process. Furthermore, we demonstrate that ethylene biosynthetic gene expressions and ethylene production are activated prematurely in GA-deficient fruits but delayed/reduced in exogenous GA3-treated WT fruits. We also show that the GA deficiency-mediated activation of ethylene biosynthesis is due to the activation of the ripening regulator genes RIN, NOR and CNR. In conclusion, our results demonstrate that GAs play a negative role in tomato fruit ripening.

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