Soluble carbohydrates and growth and develoment in the wheat apex

xvii, 214 leaves : ill., graphs, tables ; 29 cm.Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Physiology, 198

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Not AvailableIron homeostasis was studied in two tropical indica rice cultivars viz. Sharbati (high Fe) and Lalat (low Fe) having contrasting grain Fe concentration. Plants were hydroponically grown with 5 concentrations of Fe (0.05, 2, 5, 15, 50 mg L−1) till maturity. The effect of incremental Fe treatment on the plant was followed by analyzing accumulation of ferritin protein, activities of aconitase enzyme, enzymes of anti-oxidative defense and accumulation of hydrogen peroxide and ascorbic acid. Plant growth was adversely affected beyond 15 mg L−1 of Fe supplementation and effects of Fe stress (both deficiency and excess) were more apparent on the high Fe containing cultivar Sharbati than the low Fe containing Lalat. Level of ferritin protein and aconitase activity increased up to 5 mg L−1 of Fe concentration. Lalat continued to synthesize ferritin protein at much higher Fe level than Sharbati and the cultivar also had higher activities of peroxidase, superoxide dismutase and glutathione reductase. It was concluded that the tolerance of Lalat to Fe stress was because of its higher intrinsic ability to scavenge free radicals of oxidative stress for possessing higher activity of antioxidative enzymes. This, together with its capacity to sequester theexcess Fe in ferritin protein over a wider range of Fe concentrations made it more tolerant to Fe stress.Not Availabl

Controlling the trade-off between spikelet number and grain filling: the hierarchy of starch synthesis in spikelets of rice panicle in relation to hormone dynamics (vol 46, pg 507, 2019)

Corrigendum to: Controlling the trade-off between spikelet number and grain filling: the hierarchy of starch synthesis in spikelets of rice panicle in relation to hormone dynamics, Functional Plant Biology 46 (6), 2019, 595 - 595, WOS:000469437400002International audienc

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Identification and Characterization of Differentially Expressed Genes in Inferior and Superior Spikelets of Rice Cultivars with Contrasting Panicle-Compactness and Grain-Filling Properties

<div><p>Breeding programs for increasing spikelet number in rice have resulted in compactness of the panicle, accompanied by poor grain filling in inferior spikelets. Although the inefficient utilization of assimilate has been indicated as responsible for this poor grain filling, the underlying cause remains elusive. The current study utilized the suppression subtractive hybridization technique to identify 57 and 79 genes that overexpressed in the superior and inferior spikelets (with respect to each other), respectively, of the compact-panicle rice cultivar Mahalaxmi. Functional categorization of these differentially expressed genes revealed a marked metabolic difference between the spikelets according to their spatial location on the panicle. The expression of genes encoding seed storage proteins was dominant in inferior spikelets, whereas genes encoding regulatory proteins, such as serine-threonine kinase, zinc finger protein and E3 ligase, were highly expressed in superior spikelets. The expression patterns of these genes in the inferior and superior spikelets of Mahalaxmi were similar to those observed in another compact-panicle cultivar, OR-1918, but differed from those obtained in two lax-panicle cultivars, Upahar and Lalat. The results first suggest that the regulatory proteins abundantly expressed in the superior spikelets of compact-panicle cultivars and in both the superior and inferior spikelets of lax-panicle cultivars but poorly expressed in the inferior spikelets of compact-panicle cultivars promote grain filling. Second, the high expression of seed-storage proteins observed in the inferior spikelets of compact-panicle cultivars appears to inhibit the grain filling process. Third, the low expression of enzymes of the Krebs cycle in inferior spikelets compared with superior spikelets of compact-panicle cultivars is bound to lead to poor ATP generation in the former and consequently limit starch biosynthesis, an ATP-consuming process, resulting in poor grain filling.</p></div

RT-qPCR of total RNA isolated from superior and inferior spikelets of <i>O</i>. <i>sativa</i> cultivars on various days after anthesis (DAA) for five mitochondrial genes.

<p>Each bar represents the relative expression (in fold change) in superior (A) or inferior (B) spikelets of Upahar compared with those of Mahalaxmi and in superior (C) inferior (D) spikelets of Lalat compared with those of OR-1918. 19S rRNA was used as the reference gene. The genes examined included 2-oxoglutarate dehydrogenase E1 component (<i>OGDE1</i>, LOC_OS04G32020.1), succinyl CoA synthase (LOC_Os07g38970.1), succinate dehydrogenase (LOC_OS07G04240.1), isocitrate dehydrogenase (LOC_Os01g46610.1), and malate dehydrogenase (LOC_Os01g46070.1). Additional details of the analysis are described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145749#pone.0145749.g002" target="_blank">Fig 2</a>.</p