ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Senescence-induced RNases in tomato.

Lers, A.; Khalchitski, A.; Lomaniec, E.; Burd, S.; Green, P. J.;

Plant Molecular Biology Year: 1998 Vol: 36 Issue: 3 Pages: 439-449 Ref: 36 ref.

1998

บทคัดย่อ

A main feature of leaf senescence is the hydrolysis of macromolecules by hydrolases of various types, and redistribution of released materials. Using a PCR-based cloning approach, two senescence-induced RNase [ribonuclease] cDNA clones were isolated from tomato. Each of these cDNAs hybridized to a senescence-induced transcript in northern analysis. One RNase cDNA was identical to the tomato LX RNase while the second corresponded to the LE RNase. Both LX and LE RNase genes had originally been demonstrated to be induced after phosphate starvation of tomato cell culture, but nothing was known about their expression or function in plants. Expression of the LX and LE genes is induced in leaves during an advanced stage of senescence, with the LX transcript level being more highly induced than that of LE. Low-level expression of the RNase genes was observed in flowers and in artificially senescing detached leaves, while no expression was detected in stems, roots or fruits at different ripening stages.

Ethylene activated LX gene expression in detached young leaves, while LE gene expression, which could be transiently induced by wounding, appeared to be activated by abscisic acid. It is suggested that the LX RNase has a role in RNA catabolism in the final stage of senescence, while LE may function during wounding as a plant defence protein.