SummaryIn order to understand the molecular genetic mechanisms of rice (Oryza sativa) organ development, we studied the narrow leaf2 narrow leaf3 (nal2 nal3; hereafter nal2/3) double mutant, which produces narrow-curly leaves, more tillers, fewer lateral roots, opened spikelets and narrow-thin grains.We found that narrow-curly leaves resulted mainly from reduced lateral-axis outgrowth with fewer longitudinal veins and more, larger bulliform cells. Opened spikelets, possibly caused by marginal deformity in the lemma, gave rise to narrow-thin grains.Map-based cloning revealed that NAL2 and NAL3 are paralogs that encode an identical OsWOX3A (OsNS) transcriptional activator, homologous to NARROW SHEATH1 (NS1) and NS2 in maize and PRESSED FLOWER in Arabidopsis. OsWOX3A is expressed in the vascular tissues of various organs, where nal2/3 mutant phenotypes were displayed. Expression levels of several leaf development-associated genes were altered in nal2/3, and auxin transportrelated genes were significantly changed, leading to pin mutant-like phenotypes such as more tillers and fewer lateral roots.OsWOX3A is involved in organ development in rice, lateral-axis outgrowth and vascular patterning in leaves, lemma and palea morphogenesis in spikelets, and development of tillers and lateral roots.
Summary In seeds and other parts of cultivated, tetraploid cotton ( Gossypium hirsutum L.), multicellular groups of cells lysigenously form dark glands containing toxic terpenoids such as gossypol that defend the plant against pests and pathogens. Using RNA ‐seq analysis of embryos from near‐isogenic glanded ( Gl 2 Gl 2 Gl 3 Gl 3 ) versus glandless ( gl 2 gl 2 gl 3 gl 3 ) plants, we identified 33 genes that expressed exclusively or at higher levels in embryos just prior to gland formation in glanded plants. Virus‐induced gene silencing against three gene pairs led to significant reductions in the number of glands in the leaves, and significantly lower levels of gossypol and related terpenoids. These genes encode transcription factors and have been designated the ‘Cotton Gland Formation’ ( CGF ) genes. No sequence differences were found between glanded and glandless cotton for CGF 1 and CGF 2 gene pairs. The glandless cotton has a transposon insertion within the coding sequence of the Go PGF (synonym CGF 3 ) gene of the A subgenome and extensive mutations in the promoter of D subgenome homeolog. Overexpression of Go PGF (synonym CGF 3 ) led to a dramatic increase in gossypol and related terpenoids in cultured cells, whereas CRISPR /Cas9 knockout of Go PGF (synonym CGF 3 ) genes resulted in glandless phenotype. Taken collectively, the results show that the Go PGF (synonym CGF 3 ) gene plays a critical role in the formation of glands in the cotton plant. Seed‐specific silencing of CGF genes, either individually or in combination, could eliminate glands, thus gossypol, from the cottonseed to render it safe as food or feed for monogastrics.
SignificanceAn increasing number of herbicide-resistant weeds are being reported in the United States, Argentina, and Brazil. This is becoming a global challenge for the production of several major crops, such as cotton, maize, and soybean. New strategies for weed control are required to sustain agricultural production while reducing our dependence on herbicides. Here, we report that selective fertilization of transgenic cotton, expressing a bacterial phosphite dehydrogenase (PTXD), with phosphite provides an effective way to suppress weed growth. Importantly, we show that the ptxD-transgenic cotton plants successfully outcompete a highly aggressive glyphosate-resistant weed. The ptxD/phosphite system represents one of the most promising technologies of recent times with potential to solve many of the agricultural and environmental problems that we encounter currently.
SUMMARYThe zebra-necrosis (zn) mutant of rice (Oryza sativa) produces transversely green/yellow-striped leaves. The mutant phenotype is formed by unequal impairment of chloroplast biogenesis before emergence from the leaf sheath under alternate light/dark or high/low temperatures (restrictive), but not under constant light and temperature (permissive) conditions. Map-based cloning revealed that ZN encodes a thylakoid-bound protein of unknown function. Virus-induced gene silencing of a ZN homolog in Nicotiana benthamiana causes leaf variegation with sporadic green/yellow sectors, indicating that ZN is essential for chloroplast biogenesis during early leaf development. Necrotic lesions often occur in the yellow sectors as a result of an excessive accumulation of reactive oxygen species (ROS). The phenotypic severity (leaf variegation and necrosis) and ROS levels are positively correlated with an increase in light intensity under restrictive conditions. In the mutant leaves, chlorophyll (Chl) metabolism, ROS scavenging activities, maximum quantum yield of photosystem II (PSII), and structures and functions of the photosynthetic complexes are normal in the Chl-containing cells, suggesting that ROS are mainly generated from the defective plastids of the Chl-free cells. The PSII activity of normal chloroplasts is hypersensitive to photoinhibition because the recovery rates of PSII are much slower. In the PSII repair, the degradation of damaged D1 is not impaired, suggesting a reduced activity of new D1 synthesis, possibly because of higher levels of ROS generated from the Chl-free cells by excess light. Together, we propose that ZN is required for protecting developing chloroplasts, especially during the assembly of thylakoid protein complexes, from incidental light after darkness.
SummaryCottonseed remains a low-value by-product of lint production mainly due to the presence of toxic gossypol that makes it unfit for monogastrics. Ultra-low gossypol cottonseed (ULGCS) lines were developed using RNAi knockdown of d-cadinene synthase gene(s) in Gossypium hirsutum.The purpose of the current study was to assess the stability and specificity of the ULGCS trait and evaluate the agronomic performance of the transgenic lines. Trials conducted over a period of 3 years show that the ULGCS trait was stable under field conditions and the foliage/floral organs of transgenic lines contained wild-type levels of gossypol and related terpenoids. Although it was a relatively small-scale study, we did not observe any negative effects on either the yield or quality of the fibre and seed in the transgenic lines compared with the nontransgenic parental plants. Compositional analysis was performed on the seeds obtained from plants grown in the field during 2009. As expected, the major difference between the ULGCS and wild-type cottonseeds was in terms of their gossypol levels. With the exception of oil content, the composition of ULGCS was similar to that of nontransgenic cottonseeds. Interestingly, the ULGCS had significantly higher (4%-8%) oil content compared with the seeds from the nontransgenic parent. Field trial results confirmed the stability and specificity of the ULGCS trait suggesting that this RNAi-based product has the potential to be commercially viable. Thus, it may be possible to enhance and expand the nutritional utility of the annual cottonseed output to fulfil the ever-increasing needs of humanity.
Cytoplasmic male sterility (CMS) is a maternally inherited trait characterized by the inability to produce functional pollen. The CMS-associated protein Orf507 (reported as Orf456 in previous researches) was previously identified as a candidate gene for mediating male sterility in pepper. Here, we performed yeast two-hybrid analysis to screen for interacting proteins, and found that the ATP synthase 6 kDa subunit containing a mitochondrial signal peptide (MtATP6) specifically interacted with Orf507. In addition, the two proteins were found to be interacted in vivo using bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP) assays. Further functional characterization of Orf507 revealed that the encoded protein is toxic to bacterial cells. Analysis of tissue-specific expression of ATP synthase 6 kDa showed that the transcription level was much lower in anthers of the CMS line than in their wild type counterparts. In CMS plants, ATP synthase activity and content were reduced by more than half compared to that of the normal plants. Taken together, it can be concluded that reduced ATP synthase activity and ATP content might have affected pollen development in CMS plants. Here, we hypothesize that Orf507 might cause MtATP6 to be nonfunctional by changing the latter's conformation or producing an inhibitor that prevents the normal functioning of MtATP6. Thus, further functional analysis of mitochondrial Orf507 will provide insights into the mechanisms underlying CMS in plants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.