Functional Characterization of SlSAHH2 in Tomato Fruit Ripening.
Functional Characterization of SlSAHH2 in Tomato Fruit Ripening.
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DOI：
10.3389/fpls.2017.01312
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发表时间：
2017
影响因子：
5.6
通讯作者：
Li Z
中科院分区：
文献类型：
--
作者：
Yang L;Hu G;Li N;Habib S;Huang W;Li Z
S-腺苷高半胱氨酸水解酶（SAHH）作为催化S-腺苷高半胱氨酸可逆水解为高半胱氨酸和腺苷的酶起作用。在目前的工作中，我们研究了它在番茄果实成熟过程中的作用。在这三个SlSAHH基因中，我们证明了SlSAHH 2在果实成熟过程中高度积累，并且对乙烯处理有强烈的响应。SlSAHH 2的过表达增强了番茄果实发育和成熟阶段的SAHH酶活性，并导致了从开花到破壳的成熟时间缩短的主要表型变化。与此相一致，在相同的发育阶段，SlSAHH 2过表达系中番茄红素的含量高于野生型。结果表明，在转基因植株中，两个乙烯诱导基因（E4和E8）和三个乙烯生物合成基因（SlACO 1、SlACO 3和SlACS 2）的表达量在开花期都有明显提高，其中一个转基因植株的乙烯产量比野生型植株高出很多。虽然两个转基因株系在基因表达和乙烯产生方面存在差异，但RIN、AP 2a、TAGL 1、CNR和NOR等几个重要的成熟调节因子的转录水平变化具有一致性。推测SlSAHH 2对乙烯产生的影响是在SlSAHH 2对这些成熟调节基因的调控下游。过表达株系在果实和非果实组织中均表现出较高的乙烯敏感性。乙烯前体1-氨基环丙烷-1-羧酸（ACC）处理在SlSAHH 2过表达果实中比在野生型中更快地加速成熟。此外，在乙烯三重反应试验中，转基因株系的幼苗下胚轴和根都较短。综上所述，SlSAHH 2在番茄果实成熟过程中起着重要作用。
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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影响因子：
3.8
作者：
Burns, J;Fraser, PD;Bramley, PM
通讯作者：
Bramley, PM
DOI：
10.1073/pnas.88.16.7434
发表时间：
1991-08-01
影响因子：
11.1
作者：
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影响因子：
7.4
作者：
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通讯作者：
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DOI：
10.1073/pnas.76.1.170
发表时间：
1979-01-01
影响因子：
11.1
作者：
ADAMS, DO;YANG, SF
通讯作者：
YANG, SF
影响因子：
3.1
作者：
Fulnecek, Jaroslav;Matyasek, Roman;Kovarik, Ales
通讯作者：
Kovarik, Ales