Down-regulation of S-adenosyl-l-homocysteine hydrolase reveals a role of cytokinin in promoting transmethylation reactions

Li, Chunhong; Yu, Nan; Jiang, Shanwen; Shangguan, Xiao-Xia; Wang, Ling-Jian; Chen, Xiao‐Ya

doi:10.1007/s00425-008-0724-2

Cited by 44 publications

(44 citation statements)

References 55 publications

(66 reference statements)

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“…This enzyme plays a role in chromatin remodeling (e.g., HOG1, which is required for DNA methylation-dependent gene silencing, or the CHD3 remodeler PICKLE, which promotes trimethylation of histone H3), a process that regulates seed germination (124, 153). An AdoHcy hydrolase binds cytokinin with an enormous affinity; by doing so, this protein interferes with this hormonal signaling, leading to alteration in the ABA/GA balance (88). These results provide a link between cytokinins, DNA methylation, and germination (Figure 3).…”

Section: Adomet-dependent Methyltransferasesmentioning

confidence: 95%

Seed Germination and Vigor

Rajjou

Duval

Gallardo

et al. 2012

Annu. Rev. Plant Biol.

923

749

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Germination vigor is driven by the ability of the plant embryo, embedded within the seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using "-omics" approaches support the finding that a main contributor of seed germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating seed germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the seed to initiate its development toward germination. This review highlights that germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.

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Section: Adomet-dependent Methyltransferasesmentioning

confidence: 95%

Seed Germination and Vigor

Rajjou

Duval

Gallardo

et al. 2012

Annu. Rev. Plant Biol.

923

749

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“…Cytokinins were extracted and purified according to Li et al (2008). Briefly, fresh leaves (0.2 g) were ground to a fine powder in liquid N 2 and extracted with precold 80% methanol at 48C overnight.…”

Section: Measurement Of Cytokininmentioning

confidence: 99%

Posttranslational Elevation of Cell Wall Invertase Activity by Silencing Its Inhibitor in Tomato Delays Leaf Senescence and Increases Seed Weight and Fruit Hexose Level

2009

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Invertase plays multiple pivotal roles in plant development. Thus, its activity must be tightly regulated in vivo. Emerging evidence suggests that a group of small proteins that inhibit invertase activity in vitro appears to exist in a wide variety of plants. However, little is known regarding their roles in planta. Here, we examined the function of INVINH1, a putative invertase inhibitor, in tomato (Solanum lycopersicum). Expression of a INVINH1:green fluorescent protein fusion revealed its apoplasmic localization. Ectopic overexpression of INVINH1 in Arabidopsis thaliana specifically reduced cell wall invertase activity. By contrast, silencing its expression in tomato significantly increased the activity of cell wall invertase without altering activities of cytoplasmic and vacuolar invertases. Elevation of cell wall invertase activity in RNA interference transgenic tomato led to (1) a prolonged leaf life span involving in a blockage of abscisic acid-induced senescence and (2) an increase in seed weight and fruit hexose level, which is likely achieved through enhanced sucrose hydrolysis in the apoplasm of the fruit vasculature. This assertion is based on (1) coexpression of INVINH1 and a fruit-specific cell wall invertase Lin5 in phloem parenchyma cells of young fruit, including the placenta regions connecting developing seeds; (2) a physical interaction between INVINH1 and Lin5 in vivo; and (3) a symplasmic discontinuity at the interface between placenta and seeds. Together, the results demonstrate that INVINH1 encodes a protein that specifically inhibits the activity of cell wall invertase and regulates leaf senescence and seed and fruit development in tomato by limiting the invertase activity in planta.

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“…In plants, the biological function of SAHH has also been investigated in many species. AtSAHH1 and AtSAHH2 encoding two SAHH enzymes were identified in Arabidopsis (Rocha et al, 2005; Pereira et al, 2007; Li C.H. et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Functional Characterization of SlSAHH2 in Tomato Fruit Ripening

Lü

et al. 2017

Front. Plant Sci.

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S-adenosylhomocysteine hydrolase (SAHH) functions as an enzyme catalyzing the reversible hydrolysis of S-adenosylhomocysteine to homocysteine and adenosine. In the present work we have investigated its role in the ripening process of tomato fruit. Among the three SlSAHH genes we demonstrated that SlSAHH2 was highly accumulated during fruit ripening and strongly responded to ethylene treatment. Over-expression of SlSAHH2 enhanced SAHH enzymatic activity in tomato fruit development and ripening stages and resulted in a major phenotypic change of reduced ripening time from anthesis to breaker. Consistent with this, the content of lycopene was higher in SlSAHH2 over-expression lines than in wild-type at the same developmental stage. The expression of two ethylene inducible genes (E4 and E8) and three ethylene biosynthesis genes (SlACO1, SlACO3 and SlACS2) increased to a higher level in SlSAHH2 over-expression lines at breaker stage, and one transgenic line even produced much more ethylene than wild-type. Although inconsistency in gene expression and ethylene production existed between the two transgenic lines, the transcriptional changes of several important ripening regulators such as RIN, AP2a, TAGL1, CNR and NOR showed a consistent pattern. It was speculated that the influence of SlSAHH2 on ethylene production was downstream of the regulation of SlSAHH2 on these ripening regulator genes. The over-expressing lines displayed higher sensitivity to ethylene in both fruit and non-fruit tissues. Ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) treatment accelerated ripening faster in SlSAHH2 over-expressing fruit than in wild-type. Additionally, seedlings of transgenic lines displayed shorter hypocotyls and roots in ethylene triple response assay. In conclusion, SlSAHH2 played an important role in tomato fruit ripening.

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Down-regulation of S-adenosyl-l-homocysteine hydrolase reveals a role of cytokinin in promoting transmethylation reactions

Cited by 44 publications

References 55 publications

Seed Germination and Vigor

Seed Germination and Vigor

Posttranslational Elevation of Cell Wall Invertase Activity by Silencing Its Inhibitor in Tomato Delays Leaf Senescence and Increases Seed Weight and Fruit Hexose Level

Functional Characterization of SlSAHH2 in Tomato Fruit Ripening

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