บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Expression and internal feedback regulation of ACC synthase and ACC oxidase genes in ripening tomato fruit

Nakatsuka, A., Shiomi, S., Kubo, Y. and Inaba, A.

Plant and Cell Physiology Year: 1997 Vol: 38 Issue: 10 Pages: 1103-1110.

1997

บทคัดย่อ

Expression and internal feedback regulation of ACC synthase and ACC oxidase genes in ripening tomato fruit.

A study was carried out to determine whether or not a positive feedback regulation of gene expression for 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase also operates in ripening tomato fruits (cv. TVR-2) during the burst of ethylene production. Two cDNA fragments for ACC synthase and 1 for ACC oxidase were cloned with high homology to already known genes involved in ethylene biosynthesis in ripening tomato fruits. Accumulation of mRNAs which hybridize to these cDNA probes was induced in mature green fruits within 2 days by treatment with propylene. In the fruits ripened from the turning stage, red colour development, ethylene production, ACC content, and activities of ACC synthase and ACC oxidase increased as maturity progressed. The abundance of 2 ACC synthase and 1 ACC oxidase mRNAs in the fruits increased from the turning to pink stage and was followed by a slight decline towards the red stage. These increases in mRNAs abundance with ripening were prevented to a large exten

t by treatment with the ethylene action inhibitor, 1-methylcyclopropene (MCP). This was most pronounced in the fruits treated with MCP at the turning stage, in which the accumulation of ACC synthase and ACC oxidase transcripts was almost completely eliminated in the first 2 days, precisely the same stage at which the control fruits had the greatest level of each mRNA accumulation. The inhibition of transcript accumulation recovered to the control level within 2-4 days. MCP also decreased ethylene biosynthetic activity, although this decrease did not reflect the reduction in the mRNAs accumulation. These results suggest that a strong positive feedback regulation is involved in ethylene biosynthesis at the gene transcriptional level in tomato fruits, even at the stage with a burst of ethylene production.