Reference "A recessive heterochronic mutation, plastochron1, shortens the plastochron and elongates the vegetative phase in rice"

Reference ID

11205

Title

A recessive heterochronic mutation, plastochron1, shortens the plastochron and elongates the vegetative phase in rice

Source

The Plant cell, 1998, vol. 10, pp. 1511-1522

Authors (4)

Itoh-J-I	Hasegawa-A
Kitano-H	Nagato-Y

Abstract

We describe two recessive alleles of a rice heterochronic gene, plastochron1-1
(pla1-1) and pla1-2, that reduce the length of the plastochron to approximately
half that of the wild type. Because the onset of the reproductive phase in pla1
was not temporally affected, the number of leaves produced in the vegetative
phase was nearly twice that produced in the wild type. Panicle development was
severely disturbed in pla1 mutants. In pla1-1, many primordia of primary rachis
branches were converted into vegetative shoots. These ectopic shoots repeated
the initiation of panicle development and the conversion of primary rachis
branches into shoots. In the weak allele pla1-2, however, only the basal one or
two primordia developed as vegetative shoots, and the remaining primordia
developed to produce a truncated panicle. These results indicate that both
vegetative and reproductive programs are expressed simultaneously during the
reproductive phase of pla1; however, the degree varied depending on the strength
of the allele. Accordingly, pla1 is a heterochronic mutation that extends the
vegetative period. The shoot apical meristem of pla1 was larger than that of the
wild type, although the shape was not modified. An in situ hybridization
experiment using the histone H4 gene as a probe revealed that cell divisions are
accelerated in the pla1 meristem. The PLA1 gene is considered to regulate the
duration of the vegetative phase by controlling the rate of leaf production in
the meristem.