Growth-Regulating Action of Brassinolide in Rice Plants

Fujii, Seiichi; Hirai, Koichi; Saka, Hitoshi

doi:10.1021/bk-1991-0474.ch027

Cited by 23 publications

(13 citation statements)

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“…Orange and red, >2-fold and >5-fold induction, respectively; blue, >2-fold repression; yellow, no change; gray, no data. maximum carboxylation rate of Rubisco (Fujii et al, 1991;Ramraj et al, 1997;Yu et al, 2004), and our results suggest that BR levels that are elevated by transgenes can have similar effects. Although it is not clear how BRs bring about these effects on photosynthesis, the repression of the U-box ubiquitin ligase (and the possible repression of the chloroplast protease) that were conspicuous in the microarray data might have prolonged the half-lives of some of the photosynthetic proteins, and the induction of the Rubisco small subunit might have increased the capacity for carboxylation and the accumulation of sucrose.…”

Section: Increased Br Levels Favor Sucrose Accumulation In the Leaf Asupporting

confidence: 64%

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Brassinosteroids Regulate Grain Filling in Rice

et al. 2008

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Genes controlling hormone levels have been used to increase grain yields in wheat (Triticum aestivum) and rice (Oryza sativa). We created transgenic rice plants expressing maize (Zea mays), rice, or Arabidopsis thaliana genes encoding sterol C-22 hydroxylases that control brassinosteroid (BR) hormone levels using a promoter that is active in only the stems, leaves, and roots. The transgenic plants produced more tillers and more seed than wild-type plants. The seed were heavier as well, especially the seed at the bases of the spikes that fill the least. These phenotypic changes brought about 15 to 44% increases in grain yield per plant relative to wild-type plants in greenhouse and field trials. Expression of the Arabidopsis C-22 hydroxylase in the embryos or endosperms themselves had no apparent effect on seed weight. These results suggested that BRs stimulate the flow of assimilate from the source to the sink. Microarray and photosynthesis analysis of transgenic plants revealed evidence of enhanced CO 2 assimilation, enlarged glucose pools in the flag leaves, and increased assimilation of glucose to starch in the seed. These results further suggested that BRs stimulate the flow of assimilate. Plants have not been bred directly for seed filling traits, suggesting that genes that control seed filling could be used to further increase grain yield in crop plants.

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Section: Increased Br Levels Favor Sucrose Accumulation In the Leaf Asupporting

confidence: 64%

“…Like many hormones, BRs affect many plant processes, including those that control tiller number, leaf size, and leaf angle (Fujii et al, 1991;Sakamoto et al, 2005;Morinaka et al, 2006). This suggests that manipulation of BR levels in specific parts of crop plants could be one way to further increase grain yields.…”

Section: Introductionmentioning

confidence: 99%

Brassinosteroids Regulate Grain Filling in Rice

et al. 2008

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“…This ultimately results in higher leaf area and biomass production. BR application is also reported to increase translocation [6,17] resulting in increased ear number, grain number per ear and 1000 grain weight and harvest index which contributed to higher grain yields.…”

Section: Resultsmentioning

confidence: 99%

Effects of homobrassinolide application on plant metabolism and grain yield under irrigated and moisture-stress conditions of two wheat varieties

1994

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Homobrassinolide (BR) was applied either as a seed treatment or foliar spray to two contrasting wheat varieties, viz. C306 (drought tolerant) and HD2329 (drought susceptible), to examine its effects on plant metabolism and grain yield under irrigated and moisture-stress/rainfed conditions. BR application resulted in increased relative water content, nitrate reductase activity, chlorophyll content and photosynthesis under both conditions. BR application also improved membrane stability (lower injury). These beneficial effects resulted in higher leaf area, biomass production, grain yield and yield related parameters in the treated plants. All the treatments were significantly better than the untreated control. Generally, 0.05ppm either as a seed treatment or foliar spray was more effective than the 0.01 ppm treatment. The drought-tolerant genotype C306 showed more response to BR application under moisture-stress/rainfed condition than HD 2329. Increased water uptake, membrane stability and higher carbon dioxide and nitrogen assimilation rates under stress seemed to be related to homobrassinolide-induced drought tolerance.

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“…BRs aVect many plant processes including those that control leaf size, leaf angle, Xowering time, plant architecture and seed yield (Fujii et al 1991;Sakamoto et al 2006;Morinaka et al 2006). BRs gained importance through their potential to improve crop biomass and stress tolerance by genetic manipulation of BR biosynthesis and signaling (Divi and Krishna 2009).…”

Section: Introductionmentioning

confidence: 99%

Brassinosteroid leaf unrolling QTL mapping in durum wheat

Isidro

Knox

Singh

et al. 2012

Planta

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Brassinosteroids are a newly reported class of plant growth phytohormones found in plants throughout the plant kingdom. Functioning at very low concentrations, they play an essential role in improving biomass yield and stress tolerance. There are no reports in the literature of the genetic variability of responsiveness of brassinosteroids in wheat; most studies on brassinosteroids have focused on the physiological effects of exogenous addition of brassinosteroids. Our aim was to study the genetic variation in the responsiveness of a doubled haploid durum wheat population to three brassinosteroid concentrations using the leaf unrolling test, which is a simple bioassay to test brassinosteroid activity. An F(1)-derived doubled haploid population of 77 individuals from the cross Strongfield/Blackbird was used to construct a genetic map of 427 molecular marker loci. The leaf unrolling test was performed on the parents and doubled haploid genotypes of the population using 0.2, 2 and 20 nM brassinosteroid concentrations. The results indicated significant differences in leaf unrolling between the two parents, doubled haploid genotypes, treatments and genotype-by-treatment combinations. Transgressive segregation beyond Strongfield of leaf unrolling was observed for all concentrations, with the strongest response at 20 nM. Putative quantitative trait loci were revealed in the intervals Xgwm2-Xbarc45 on chromosome 3A and Xwmc643a-Xwmc625a on chromosome 3B. Additional quantitative trait loci were associated with markers Xwmc48a, Xwmc511, Xwmc89a and Xgwmc692 on chromosome 4B, and Xwmc17 on chromosome 7A. This work should enhance the understanding of the relationship between stress tolerance and productivity, and responsiveness to brassinosteroids.

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Growth-Regulating Action of Brassinolide in Rice Plants

Cited by 23 publications

References 0 publications

Brassinosteroids Regulate Grain Filling in Rice

Brassinosteroids Regulate Grain Filling in Rice

Effects of homobrassinolide application on plant metabolism and grain yield under irrigated and moisture-stress conditions of two wheat varieties

Brassinosteroid leaf unrolling QTL mapping in durum wheat

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