Morphological characteristics and gene mapping of a palea degradation(<I>pd2</I>) mutant in rice

Abstract

The yield and quality of rice are directly impacted by floral organ development in rice. Understanding of the floral development mechanism will be useful in genetic improvement of yield and quality. In this study, a rice mutant palea degradation 2 (pd2) in an indica cultivar '8PW33' was obtained after 60Co γ-ray treatment. Analysis of the mutant showed that, compared to the wild type, plant height, total grain number per panicle, and sword leaf width were significantly increased, but the seed setting rate were significantly decreased. The florets of the mutant exhibited degraded palea and sickle-shaped tortuous lemma. Detail examination using scanning electron microscopy revealed that when epidermis of the vane and lemma were normal, epidermis of the palea were arranged tightly, which might result from degraded palea. Genetic analysis supported that this mutation phenotype was controlled by a single recessive gene. Polymorphic analysis of simple sequence repeat markers demonstrated that PD2 gene is located on chromosome 9. With a larger mapping population and more indel markers, we further mapped PD2 gene between 2 indel markers with a physical region of about 82 kb. Within this region, there is a cloned gene REP1 known to control rice palea development. By comparing the DNA sequences of REP1 from pd2 and 8PW33, in combination with the results of phenotypic analysis, we concluded that PD2 is an allele of REP1.

Identification and fine mapping oflemma-distortion1, a single recessive gene playing an essential role in the development of lemma in rice

“…LIP1 and LIP2 genes are members of the AP2-like genes in A. majus, which is also involved in determining floral organ identities (Keck et al 2003). In rice, the DL gene (Yamaguchi et al 2004), PAL1 (Luo et al 2005), SL1 (Xiao et al 2009) and REP1, SDP1 or DP2 (Yuan et al 2009;Jin et al 2011;Yang et al 2012) have been identified as genes involved in floral development, but they do not belong to either the MADS-box nor AP2 gene families in rice. These results imply that a non-ABC-class gene may specify rice palea/lemma identity.…”

“…2011; Yang et al . 2012) have been identified as genes involved in floral development, but they do not belong to either the MADS-box nor AP2 gene families in rice. These results imply that a non-ABC-class gene may specify rice palea/lemma identity.…”

“…A rice floral mutant, pd2 , was identified previously (Yang et al . 2012). The florets of the pd2 mutant exhibited degraded palea and sickle-shaped tortuous lemma.…”

“…Further research determined that PD2 and REP1 were alleles at the same genetic location (Yang et al . 2012). Research indicated that REP1 encoded a TCP gene.…”

“…However, compared with the wild-type, the pd2 mutant showed normal development of rudimentary and empty glumes, lemma, two lodicules, six stamens and one pistil. Further research determined that PD2 and REP1 were alleles at the same genetic location (Yang et al 2012). Research indicated that REP1 encoded a TCP gene.…”