Article

Rice Plant Development: from Zygote to Spikelet

Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-865 Japan.
Plant and Cell Physiology (Impact Factor: 4.93). 02/2005; 46(1):23-47. DOI: 10.1093/pcp/pci501
Source: PubMed

ABSTRACT

Rice is becoming a model plant in monocotyledons and a model cereal crop. For better understanding of the rice plant, it is essential to elucidate the developmental programs of the life cycle. To date, several attempts have been made in rice to categorize the developmental processes of some organs into substages. These studies are based exclusively on the morphological and anatomical viewpoints. Recent advancement in genetics and molecular biology has given us new aspects of developmental processes. In this review, we first describe the phasic development of the rice plant, and then describe in detail the developmental courses of major organs, leaf, root and spikelet, and specific organs/tissues. Also, for the facility of future studies, we propose a staging system for each organ.

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Available from: Hidemi Kitano, Oct 19, 2014
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    • "Moreover, GA is critical for pollen formation and pollen tube growth (Singh et al. 2002; Chhun et al. 2007), and GA signaling pathways are conserved between rice and Arabidopsis (Hedden and Phillips 2000; Fleet and Sun 2005). In particular , the homology of several factors involved in GA signaling and the strong similarities in stamen development between Arabidopsis and rice indicate the existence of conserved pathways of anther and pollen development within angiosperms (Chen et al. 2005; Itoh et al. 2005b; Wilson and Zhang 2009; Plackett et al. 2011). Phenotypic screens, such as those for GA-insensitive dwarf or slender-type mutants in Arabidopsis and rice, have identified several genes necessary for GA-responsive signaling (Aya et al. 2009). "
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    ABSTRACT: Gibberellic acid (GA; or gibberellin) affects the development of floral organs, especially anthers and pollen, and perturbation of development of male floral organs can cause sterility. Many studies of GA signaling have concentrated on anther development, but the effect of GA on grain production remains to be examined. Using a cross of 'Milyang23 (M23)', which has a functional allele of Early flowering1 (EL1), and 'H143', which has a nonfunctional el1 allele, we generated heterogeneous inbred family-near isogenic lines (HNILs) that are homozygous for EL1 [HNIL(M23)] or el1 [HNIL(H143)]. Here, we found that HNIL(H143) exhibited anther deformities and low pollen viability. The expression of GAMYB, a major activator of GA signaling, and its downstream genes CYP703A3 and KAR, mainly involved in pollen formation, increased abnormally during spikelet development; this activation of GA signaling may cause the sterility. To confirm the negative effect of the el1 mutation on spikelet fertility, we examined a line carrying a T-DNA insertion el1 mutant [hereafter ZH11(el1)] and its parental cultivar 'Zhonghua11 (ZH11)'. ZH11(el1) showed nearly identical defects in anther development and pollen viability as HNIL(H143), leading to decreased seed setting rate. However, the elite japonica cultivar Koshihikari, which has a nonfunctional el1 allele for early flowering in long days, produces fertile spikelets and normal grain yields, like other elite japonica cultivars. This indicates that as-yet-unknown regulator(s) that can overcome the male sterile phenotype of the el1 mutation must have been introduced into Koshihikari. The el1 mutation contributes to early flowering in japonica rice under long days but fails to limit GA signaling, thus negatively affecting spikelet fertility, which results in a loss of grain yield. Thus, EL1 is essential for photoperiod sensitivity in flowering as well as spikelet fertility in grain production.
    Full-text · Article · Dec 2015 · Rice
    • "On the other hand, the high proportion of heat-induced genes in N22 that are also expressed at high levels at the later stages of anther development is remarkable (Supplementary Figure 1and Supplementary Table 2). Note that many of these genes are also up-regulated in earlier stages (0.3- 0.6 mm anther length) coinciding with the establishment of pollen mother cells and meiosis, stages An3 and An4 described byItoh et al. (2005). Microsporogenesis is also a heat-sensitive stage during pollen development (Endo et al. 2009). "
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    ABSTRACT: Rice is one of the main food crops in the world. In the near future, yield is expected to be under pressure due to unfavourable climatic conditions, such as increasing temperatures. Therefore, improving rice germplasm in order to guarantee rice production under harsh environmental conditions is of top priority. Although many physiological studies have contributed to understand heat responses during anthesis, the most heat sensitive stage, molecular data is still largely lacking. In this study, an RNA-sequencing approach of heat- and control-treated reproductive tissues during anthesis was carried out using N22, one of the most heat tolerant rice cultivars known to date. This analysis revealed that expression of genes encoding a number of transcription factor families, together with signal transduction and metabolic pathway genes, is repressed. On the other hand, expression of genes encoding heat shock -factors and -proteins was highly activated. Many of these genes are predominantly expressed at late stages of anther development. Further physiological experiments using heat-tolerant N22 and two sensitive cultivars suggest that reduced yield in heat-sensitive plants may be associated with poor pollen development or production in anthers prior anthesis. In parallel, induction levels of a set of heat-responsive genes in these tissues correlated well with heat tolerance. Altogether, these findings suggest that proper expression of protective chaperones in anthers is needed before anthesis to overcome stress damages and to ensure fertilization. Genes putatively controlling this process were identified and are valuable candidates to consider for molecular breeding of highly productive heat tolerant cultivars.
    No preview · Article · Nov 2015 · Plant and Cell Physiology
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    • "The fertility of rice pollen grains is a critical agronomic trait affecting rice yield, and pollen sterility eliminates the difficulty of emasculation, thus it is a simple but effective way for hybrid rice production (Cheng et al. 2007; Li et al. 2007). Production of pollen is a critical process of sexual plants during anther development in the lifecycle (Itoh et al. 2005). Briefly, anther primordial cells generate meiocytes and four lobed cell layers, including the epidermis, endothecium, middle layer, and tapetum. "
    Dataset: JIPB-ABCG15

    Full-text · Dataset · Aug 2015
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