Australian Oryza: Utility and Conservation

Henry, Robert J.; Rice, Nicole F; Waters, Daniel Le; Kasem, Shabana; Ishikawa, Ryuji; Yin, Huajun; Dillon, Sally L; Crayn, Darren M.; Wing, Rod A.; Vaughan, Duncan A.

doi:10.1007/s12284-009-9034-y

Cited by 62 publications

(80 citation statements)

References 27 publications

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“…This diversity in the genus is an important resource, which is being studied to improve rice yield, especially under unfavorable environmental conditions. In particular, O. glaberrima, Oryza australiensis, and Oryza meridionalis are of interest as drought-tolerant species (Henry et al, 2010;Ndjiondjop et al, 2010;Scafaro et al, 2011Scafaro et al, , 2012, while Oryza coarctata is salt tolerant (Sengupta and Majumder, 2010). In this study, a total of 43 leaf functional and structural parameters were collected on 24 accessions corresponding to 17 species within eight genomes (Table I) to represent the spectrum of the leaf diversity in the genus Oryza.…”

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Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza)

et al. 2013

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The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO 2 access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thick leaf ), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (S mes ), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO 2 diffusion (g m ), stomatal conductance to gas diffusion (g s ), and the g m /g s ratio. While net photosynthetic rate was positively correlated with g m , neither was significantly linked with any individual structural traits. The results suggest that changes in g m depend on covariations of multiple leaf (S mes ) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thick leaf and transpiration rate and a significant positive association between Thick leaf and leaf transpiration efficiency. Interestingly, high g m together with high g m /g s and a low S mes /g m ratio (M resistance to CO 2 diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

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Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza)

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“…Australia is a center of diversity and the possible origin of the AA genome group (Brozynska et al, 2017). There is considerable scientific interest in the wild species because of their potential to be used in rice breeding programs (Henry et al, 2010) but also because of the risks they pose to rice production by acting as reservoirs of pests and pathogens (Khemmuk et al, 2016;Petrovic et al, 2013). The fungus Pyricularia oryzae, the cause of blast disease, is thought to have jumped from wild to domesticated rice in north Queensland, an event that has led to the temporary abandonment of cropping in parts of Cape York Peninsula until disease management strategies can be devised (Khemmuk et al, 2016).…”

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“…Taxon A and Oryza sp. Taxon B), grow on flood plains and the fringes of lagoons, and are perennial, dying back to buried rhizomes during the dry season (Henry et al, 2010). Many perennial monocots, such as sugarcane and banana, support large assemblages of plant viruses, probably due to the fact that infections persist from one generation to the next via vegetative propagation of the plants e.g.…”

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Novel mastreviruses identified in Australian wild rice

et al. 2017

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“…Although it might be argued that these reported new taxa are hybrid swarms originating from crosses between O. sativa and Australian wild rice, these authors have discounted this, based on molecular data. O. rufipogon was initially thought to occur in both Asia and Australia (Henry et al 2009;Vaughan 1994), with ecological and geographical isolation causing the observed genetic differentiation. However, some scientists believe that this may have been inaccurate and suggest the germplasm originally christened as O. rufipogon from Australia in fact represents the two newly identified taxa (Brozynska et al 2014).…”

Section: Relationship Between O Rufipogon O Sativa and O Nivaramentioning

confidence: 99%

“…While information on the utilization and conservation of other wild species have been reviewed (e.g. Henry et al 2009;Song et al 2005), no such efforts have been made for the African Oryza species. This chapter provides an overview of the status of conservation and utilization of African Oryza species and identifies gaps in knowledge and opportunities for further research.…”

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Genomic characterization of African cultivated and wild Oryza species

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Rice is the most important crop in the world, acting as the staple food for over half of the world's population. It belongs to the Oryza genus and has a wide genetic diversity of both wild and cultivated species, with a substantial proportion of this diversity being found in Africa. In this thesis, African cultivated and wild Oryza species have been characterized using genomic tools with the goal of promoting their conservation and utilization. A desk based study aimed at documenting the current state of conservation and utilization of African Oryza genetic resources revealed that they remain under collected and hence underrepresented in germplasm collections. Moreover, they are under-characterized and therefore grossly underutilized. In order to obtain maximum benefits from these resources, it is imperative that they are collected, efficiently conserved and optimally utilized. Efficient conservation and utilization of the Oryza gene pool is however hindered by lack of conclusive, consistent and well resolved phylogenetic and evolutionary relationships between the various cultivated and wild species. This study therefore sought to define the genetic and evolutionary relationships between the various wild and cultivated African species that form part of the AA genome group. This was done by reconstructing the phylogeny of Oryza AA genome species by massive parallel sequencing of whole chloroplast genomes. The analysis resulted in a well resolved and strongly supported phylogeny of the AA genome species showing strong genetic differentiation.The clearly defined relationships between the various taxa provide a robust platform for supporting the conservation and utility of these species. In an effort at promoting utility of these species, their starch physicochemical properties and the functional diversity relating to these starch related traits were analyzed. African rice was found to have some unique starch structure and properties, among these being high amylose content which is higher than in Asian rice. Amylose content is a key starch trait in rice. The health benefits of high amylose foods are increasingly getting recognized. African rice therefore seems to be a valuable genetic resource for breeding premium-value genotypes with high amylose content. The deployment of African rice genetic resources in rice improvement is however constrained by the inadequate understanding of the genetic mechanism underlying their unique starch traits, specifically amylose content. First, this study analysed key starch biosynthesis genes in the genomes of various cultivated and wild Oryza species. The analysis revealed that the pullulanase gene has undergone gene duplication in African rice. This apparent gene duplication was characterized with the aim of understanding whether itiii could be the molecular mechanism underlying high amylose in African rice. It was hypothesized that this gene duplication may have led to increased pullulanase activity which may have subsequently led to unique starch structure and properties...

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Australian Oryza: Utility and Conservation

Cited by 62 publications

References 27 publications

Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza)

Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza)

Novel mastreviruses identified in Australian wild rice

Genomic characterization of African cultivated and wild Oryza species

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