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4.
Salinity affects more than 6% of the world’s total land area, causing massive losses in crop yield. Salinity inhibits plant growth and development through osmotic and ionic stresses; however, some plants exhibit adaptations through osmotic regulation, exclusion, and translocation of accumulated Na+ or Cl-. Currently, there are no practical, economically viable methods for managing salinity, so the best practice is to grow crops with improved tolerance. Germination is the stage in a plant’s life cycle most adversely affected by salinity. Barley, the fourth most important cereal crop in the world, has outstanding salinity tolerance, relative to other cereal crops. Here, we review the genetics of salinity tolerance in barley during germination by summarizing reported quantitative trait loci (QTLs) and functional genes. The homologs of candidate genes for salinity tolerance in Arabidopsis, soybean, maize, wheat, and rice have been blasted and mapped on the barley reference genome. The genetic diversity of three reported functional gene families for salt tolerance during barley germination, namely dehydration-responsive element-binding (DREB) protein, somatic embryogenesis receptor-like kinase and aquaporin genes, is discussed. While all three gene families show great diversity in most plant species, the DREB gene family is more diverse in barley than in wheat and rice. Further to this review, a convenient method for screening for salinity tolerance at germination is needed, and the mechanisms of action of the genes involved in salt tolerance need to be identified, validated, and transferred to commercial cultivars for field production in saline soil. 相似文献
6.
Novel bacterial blight (BB) resistance gene(s) for rice was (were) introduced into a cultivated japonica rice variety Oryza sativa (cv. 8411), via somatic hybridization using the wild rice Oryza meyeriana as the donor of the resistance gene(s). Twenty-nine progenies of somatically hybridized plants were obtained. Seven somatically
hybridized plants and their parents were used for AFLP (amplified fragment length polymorphism) analysis using 8 primer pairs.
Results confirmed that these plants were somatic hybrids containing the characteristic bands of both parents. The morphology
of the regenerated rice showed characters of both O. sativa and O. meyeriana. Two somatic hybrids showed highest BB resistance and the other 8 plants showed moderate resistance. The new germplasms with
highest resistance have been used in the rice breeding program for the improvement of bacterial blight resistance.
Project (No. 98001) supported by Ningbo Agriculture Key Scientific Research Foundation, China 相似文献
7.
Insertion mutagenesis has become one of the most popular methods for gene functions analysis. Here we report a two-element Ac/Ds transposon system containing enhancer trap and gene trap for gene tagging in rice. The excision of Ds element was examined by PCR amplification. The excision frequency of Ds element varied from 0% to 40% among 20 F 2 populations derived from 11 different Ds parents. Southern blot analysis revealed that more than 70% of excised Ds elements reinserted into rice genome and above 70% of the reinserted Ds elements were located at different positions of the chromosome in rice. The result of histochemical GUS analysis indicated
that 28% of enhancer trap and 22% of gene trap tagging plants displayed GUS activity in leaves, roots, flowers or seeds. The
GUS positive lines will be useful for identifying gene function in rice.
Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA2Z1003) 相似文献
9.
AtCRE1 is known to be a cytokinin receptor in Arabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver
domains. The N-terminal CHASE domain of AtCRE1 contains putative recognition sites for cytokinin. Five CHASE domains containing proteins were found in rice, osCRL1 a, OsCRL1 b, OsCRL2, OsCRL3, and OsCRL4. OsCRL1 a, OsCRL1 b, OsCRL2 and OsCRL3 contain the four domains existing in CRE1, whereas OsCRL4 only contains the CHASE domain and a putative Ser/Thr protein kinase domain. The authors cloned the encoding gene OsCRL4 and found that it represents a new member of the cytokinin receptor protein in rice.
Project supported by the National Natural Science Foundation of China 相似文献
10.
Fasciclin family proteins have been identified as cell adhesion molecules in various organisms. In this study, a novel Magnaporthe oryzae fasciclin-like protein encoding gene, named MoFLP1, was isolated from a subtractive suppressive cDNA library and functionally analyzed. Sequence analysis showed that the MoFLP1 gene contains an open reading frame (ORF) of 1050 nucleotides encoding 349 amino acids with a calculated molecular weight
of 35.85 kDa and a pI of 7.76. The deduced MoFLP1 protein contains a 17-amino acid secretion signal sequence and an 18-amino
acid sequence with the characteristics of a glycosylphosphotidylinositol (GPI) anchor additional signal at its N- and C-terminuses,
respectively. Potential N-glycosylation sites and domains involving cell adhesion were also identified in MoFLP1. Sequence analysis and subcellular
localization by the expression of MoFLP1-GFP fusion construct in M. oryzae indicated that the MoFLP1 protein is probably localized on the vacuole membrane. Two MoFLP1 null mutants generated by targeted gene disruption exhibited marked reduction of conidiation, conidial adhesion, appressorium
turgor, and pathogenicity. Our results indicate that fasciclin proteins play important roles in fungal development and pathogenicity
in M. oryzae.
Project supported by the National Natural Science Foundation of China (No. 30870101) and the Public Welfare Profession (Agriculture)
Research Project (No. 200803008), China 相似文献
11.
Three genes encoding for fungal cell wall degrading enzymes (CWDEs), ech42, nag70 and glu78 from the biocontrol fungus Trichoderma atroviride were inserted into the binary vector pCAMBIA1305.2 singly and in all possible combinations and transformed to rice plants.
More than 1800 independently regenerated plantlets in seven different populations (for each of the three genes and each of
the four gene combinations) were obtained. The ech42 gene encoding for an endochitinase increased resistance to sheath blight caused by Rhizoctonia solani, while the exochitinase-encoding gene, nag70, had lesser effect. The expression level of endochitinase but exochitinase was correlated with disease resistance. Nevertheless,
exochitinase enhanced the effect of endochitinase on disease resistance when the two genes co-expressed in transgenics. Resistance
to Magnaporthe grisea was found in all kinds of regenerated plants including that with single gluc78. A few lines expressing either ech42 or nag70 gene were immune to the disease. Transgenic plants are being tested to further evaluate disease resistance at field level.
This is the first report of multiple of expression of genes encoding CWDEs from Trichoderma atroviride that result in resistance to blast and sheath blight in rice.
Project (No. 3997002) supported by the National Natural Science Foundation of China 相似文献
12.
Seed vigor is an important characteristic of seed quality, and rice cultivars with strong seed vigor are desirable in direct-sowing
rice production for optimum stand establishment. In the present study, the quantitative trait loci (QTLs) of three traits
for rice seed vigor during the germination stage, including germination rate, final germination percentage, and germination
index, were investigated using one recombinant inbred line (RIL) population derived from a cross between japonica Daguandao and indica IR28, and using the multiple interval mapping (MIM) approach. The results show that indica rice presented stronger seed vigor during the germination stage than japonica rice. A total of ten QTLs, and at least five novel alleles, were detected to control rice seed vigor, and the amount of variation
( R
2) explained by an individual QTL ranged from 7.5% to 68.5%, with three major QTLs with R
2>20%. Most of the QTLs detected here are likely to coincide with QTLs for seed weight, seed size, or seed dormancy, suggesting
that the rice seed vigor might be correlated with seed weight, seed size, and seed dormancy. At least five QTLs are novel
alleles with no previous reports of seed vigor genes in rice, and those major or minor QTLs could be used to significantly
improve the seed vigor by marker-assisted selection (MAS) in rice. 相似文献
13.
Analyses of the correlation between hyperspectral reflectance and pigment content including chlorophyll-a, chlorophyll-b and
carotenoid of leaves in different sites of rice were reported in this paper. The hyperspectral reflectance of late rice during
the whole growing season was measured using a Spectroradiometer with spectral range of 350–1050 nm and resolution of 3 nm.
The chlorophyll-a, chlorophyll-b and carotenoid contents in rice leaves in rice fields to which different levels of nitrogen
were applied were measured. The chlorophyll-a content of upper leaves was well correlated with the spectral variables. However,
the correlation between both chlorophyll-b and caroteniod and the spectral variables was far from that of chlorophyll-a. The
potential of hyperspectral reflectance measurement for estimating chlorophyll-a of upper leaves was evaluated using univariate
correlation and multivariate regression analysis methods with different types of predictors. This study showed that the most
suitable estimated model of chlorophyll-a of upper leaves was obtained by using some hyperspectral variables such as SD
r, SD
b and their integration.
Project (No. 40171065) supported by the National Natural Science Foundation of China. 相似文献
15.
Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6-phosphate is the
preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6-phosphate/phosphate translocator
( GPT) was isolated from a cDNA library of immature seeds of rice and named as OsGPT. The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of
70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000-grain weight. The expression of OsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6-phosphate imported via GPT can be used for starch biosynthesis in rice nongreen plastids.
Project supported by National Natural Scienc Foundation of China (No.39830250) and Natural Science Foundation of Zhejiang
Province (No.2A0106), China. The nucleotide sequence data will appear in the GenBank under accession number AF375053. 相似文献
16.
Magnaporthe oryzae has been used as a primary model organism for investigating fungus-plant interaction. Many researches focused on molecular
mechanisms of appressorium formation to restrain this fungal pathogen. Autophagy is a very high conserved process in eukaryotic
cells. Recently, autophagy has been considered as a key process in development and differentiation in M. oryzae. In this report, we present and discuss the current state of our knowledge on gene expression in appressorium formation and
the progress in autophagy of rice blast fungi.
Project supported by the National Natural Science Foundation of China (Nos. 30671351 and 30870101) and the Hi-Tech Research
and Development Program (863) of China (No. 2002AA245041) 相似文献
17.
The protein encoded by CC chemokine receptor 7 (CCR7) is a member of the G protein-coupled receptor family. This receptor was identified as a gene induced by the Epstein-Barr virus (EBV), and is thought to be a mediator of EBV effects on B lymphocytes. This receptor is expressed in various lymphoid tissues and activates B and T lymphocytes. It has been shown to control the migration of memory T cells to inflamed tissues, as well as stimulate dendritic cell maturation. To map the CCR7 gene in chicken chromosome, a 6000 rads chicken-hamster radiation hybrid panel (ChickRH6) was used. PCR of samples from ChickRH6 revealed that the location of CCR7 gene is linked to the maker SEQ0347 (6 cR away) with LOD score of 16.6 and that the marker SEQ0347 is located on chromosome 27 at 27 cR of RH (radiation hydrid) map. We compared the corresponding human mRNA sequence with the predicted coding sequence of chicken CCR7 gene, and found that the assembled contig shared a high percentage of similarity with that of the human gene. 相似文献
18.
Rice straw is always regarded as a by-product of rice production, but it could be a significant energy source for ruminant
animals. Knowledge of the genetic variation and genetic architecture of cell wall traits will facilitate rice breeders by
improving relevant traits through selective breeding and genetic engineering. The common wild rice, Oryza rufipogon Griff., which is considered to be the progenitor of Oryza sativa, has been widely utilized for the identification of genes of agronomic importance for rice genetic improvement. In the present
study, the mapping of quantitative trait loci (QTLs) for acid detergent fiber (ADF), neutral detergent fiber (NDF), acid detergent
lignin (ADL), and ADL/NDF ratio was carried out in two environments using a backcrossed inbred line (BIL) population derived
from a cross between the recurrent parent Xieqingzao B (XB) and an accession of Dongxiang wild rice (DWR). The results indicated
that all four traits tested were continuously distributed among the BILs, but many BILs showed transgressive segregation.
A total of 16 QTLs were identified for the four traits, but no QTLs were in common in two environments, suggesting that environment
has dramatic effects on fiber and lignin syntheses. Compared to the QTL positions for grain yield-related traits, there were
no unfavorable correlations between grain yield components and cell wall traits in this population. The QTLs identified in
this study are useful for the development of dual-purpose rice varieties that are high in grain yield and are also high in
straw quality. 相似文献
19.
ABSTRACTResearch Findings. The current study is a mixed-methods investigation of family child care provider participation in voluntary Quality Rating and Improvement Systems (QRIS) in 2 states. Study 1 is an analysis of matched QRIS and child care licensing administrative data extracted from both states in May, 2014. Poverty and population density variables were added to the dataset by aligning U.S. Census data and Rural Urban Commuting Area codes (RUCA) to the matched state child care data. Participation patterns differed in the 2 states relative to provider characteristics (subsidy receipt, years licensed, and location). Study 2 consists of focus groups with participating ( n = 22) and non-participating ( n = 19) providers. Professionalism and financial incentives emerged as significant in attracting family child care providers to QRIS. Although family child care providers identified several clear benefits to QRIS, many more challenges emerged that negatively impact their participation. Practice or Policy. As most states are employing a QRIS framework to integrate quality improvement efforts, perspectives from this sector of early care and education are often overlooked. Study findings suggest that QRIS can be more responsive and effective with family child care providers if more consideration of their unique features are considered in systems design and implementation. 相似文献
20.
《红楼梦》中,贾宝玉自比"老杨树"是有深义的。"杨树"这一意象代表了贾宝玉的平民思想,体现了贾宝玉的逍遥感和虚无感。同时,"杨树"也是红楼女儿花的保护树。"坟"这一意象在《红楼梦》中也有着特殊的美学意义。 相似文献
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