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1.
With the aid of radioactive phosphorus and gamma rays, a number of morphological and biochemical mutants ofColletotrichum capsici have been induced and these showed wide range of variability. Biochemical mutants mostly induced by means of p32 irradiation showed deficiency of amino acids or vitamins. Specific deficiency analysis of some of the biochemical mutants revealed requirements for lysine, methionine, glycine or serine and biotin. These biochemical mutants could not be distinguisbed from the wild type in morphological characters when grown on complete or otherwise suitable supplemented media. 相似文献
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Pradhan Satyabrata Singh Sanjay Kumar Srivastav Manish Prakash Jai Lal Sanjay Kumar Padaria Jasdeep Chatrath Goswami Amit Kumar Maurya Naveen Kumar 《Plant Cell, Tissue and Organ Culture》2021,145(1):155-172
Plant Cell, Tissue and Organ Culture (PCTOC) - A method for in vitro screening and selection of drought (moisture stress) tolerant mango calli was developed. Poly ethylene glycol (PEG) (Molecular... 相似文献
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Ajith Anand Emily Wu Zhi Li Sue TeRonde Maren Arling Brian Lenderts Jasdeep S. Mutti William Gordon‐Kamm Todd J. Jones Nicholas Doane Chilcoat 《Plant biotechnology journal》2019,17(8):1636-1645
An efficient Agrobacterium‐mediated site‐specific integration (SSI) technology using the flipase/flipase recognition target (FLP/FRT) system in elite maize inbred lines is described. The system allows precise integration of a single copy of a donor DNA flanked by heterologous FRT sites into a predefined recombinant target line (RTL) containing the corresponding heterologous FRT sites. A promoter‐trap system consisting of a pre‐integrated promoter followed by an FRT site enables efficient selection of events. The efficiency of this system is dependent on several factors including Agrobacterium tumefaciens strain, expression of morphogenic genes Babyboom (Bbm) and Wuschel2 (Wus2) and choice of heterologous FRT pairs. Of the Agrobacterium strains tested, strain AGL1 resulted in higher transformation frequency than strain LBA4404 THY‐ (0.27% vs. 0.05%; per cent of infected embryos producing events). The addition of morphogenic genes increased transformation frequency (2.65% in AGL1; 0.65% in LBA4404 THY‐). Following further optimization, including the choice of FRT pairs, a method was developed that achieved 19%–22.5% transformation frequency. Importantly, >50% of T0 transformants contain the desired full‐length site‐specific insertion. The frequencies reported here establish a new benchmark for generating targeted quality events compatible with commercial product development. 相似文献
4.
The abundance and inherent potential for variations in simple sequence repeats (SSRs) or microsatellites resulted in valuable source for genetic markers in
eukaryotes. We describe the organization and abundance of SSRs in fungus Fusarium graminearum (causative agent for Fusarium head blight or head
scab of wheat). We identified 1705 SSRs of various nucleotide repeat motifs in the sequence database of F. graminearum. It is observed that
mononucleotide repeats (62%) were most abundant followed by di- (20%) and trinucleotide repeats (14%). It is noted that tetra-, penta- and
hexanucleotide repeats accounted for only 4% of SSRs. The estimated frequency of Class I SSRs (perfect repeats ≥20 nucleotides) was one SSR per 124.5
kb, whereas the frequency of Class II (perfect repeats >10 nucleotides and ≫20 nucleotides) was one SSR per 25.6 kb. The dynamics of SSRs will be a
powerful tool for taxonomic, phylogenetic, genome mapping and population genetic studies as SSR based markers show high levels of allelic variation,
codominant inheritance and ease of analysis. 相似文献
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6.
Jungers WL Lemelin P Godfrey LR Wunderlich RE Burney DA Simons EL Chatrath PS James HF Randria GF 《Journal of human evolution》2005,49(1):36-55
Recent expeditions to Madagascar have recovered abundant skeletal remains of Archaeolemur, one of the so-called "monkey lemurs" known from Holocene deposits scattered across the island. These new skeletons are sufficiently complete to permit reassembly of entire hands and feet--postcranial elements crucial to drawing inferences about substrate preferences and positional behavior. Univariate and multivariate analysis of intrinsic hand and foot proportions, phalangeal indices, relative pollex and hallux lengths, phalangeal curvature, and distal phalangeal shape reveal a highly derived and unique morphology for an extinct strepsirrhine that diverges dramatically from that of living lemurs and converges in some respects on that of Old World monkeys (e.g., mandrills, but not baboons or geladas). The hands and feet of Archaeolemur are relatively short (extremely so relative to body size); the carpus and tarsus are both "long" relative to total hand and foot lengths, respectively; phalangeal indices of both the hands and feet are low; both pollex and hallux are reduced; the apical tufts of the distal phalanges are very broad; and the proximal phalanges are slightly curved (but more so than in baboons). Overall grasping capabilities may have been compromised to some extent, and dexterous handling of small objects seems improbable. Deliberate and noncursorial quadrupedalism was most likely practiced on both the ground and in the trees. A flexible locomotor repertoire in conjunction with a eurytopic trophic adaptation allowed Archaeolemur to inhabit much of Madagascar and may explain why it was one of the latest surviving subfossil lemurs. 相似文献
7.
Traits and selection strategies to improve root systems and water uptake in water-limited wheat crops 总被引:7,自引:0,他引:7
Wasson AP Richards RA Chatrath R Misra SC Prasad SV Rebetzke GJ Kirkegaard JA Christopher J Watt M 《Journal of experimental botany》2012,63(9):3485-3498
Wheat yields globally will depend increasingly on good management to conserve rainfall and new varieties that use water efficiently for grain production. Here we propose an approach for developing new varieties to make better use of deep stored water. We focus on water-limited wheat production in the summer-dominant rainfall regions of India and Australia, but the approach is generally applicable to other environments and root-based constraints. Use of stored deep water is valuable because it is more predictable than variable in-season rainfall and can be measured prior to sowing. Further, this moisture is converted into grain with twice the efficiently of in-season rainfall since it is taken up later in crop growth during the grain-filling period when the roots reach deeper layers. We propose that wheat varieties with a deeper root system, a redistribution of branch root density from the surface to depth, and with greater radial hydraulic conductivity at depth would have higher yields in rainfed systems where crops rely on deep water for grain fill. Developing selection systems for mature root system traits is challenging as there are limited high-throughput phenotyping methods for roots in the field, and there is a risk that traits selected in the lab on young plants will not translate into mature root system traits in the field. We give an example of a breeding programme that combines laboratory and field phenotyping with proof of concept evaluation of the trait at the beginning of the selection programme. This would greatly enhance confidence in a high-throughput laboratory or field screen, and avoid investment in screens without yield value. This approach requires careful selection of field sites and years that allow expression of deep roots and increased yield. It also requires careful selection and crossing of germplasm to allow comparison of root expression among genotypes that are similar for other traits, especially flowering time and disease and toxicity resistances. Such a programme with field and laboratory evaluation at the outset will speed up delivery of varieties with improved root systems for higher yield. 相似文献
8.
Muthuvel Jayachandran Hiroya Okano Ritu Chatrath Whyte G Owen Joseph P McConnell Virginia M Miller 《Journal of applied physiology》2004,97(4):1445-1452
Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2-3 mo) and sexually mature (adult; 5-6 mo) male and female pigs (n=8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 microM) and collagen (6 microg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet fibrinogen receptor, P-selectin expression, and receptors for sex steroids did not change with sexual maturation. Plasma C-reactive protein and brain-type natriuretic peptide also did not change. Results indicate that changes in platelet aggregation and secretion change with sexual maturity differently in females and males. These observations provide evidence on which clinical studies could be designed to examine platelet characteristics in human children and young adults. 相似文献
9.
Jasdeep S. Mutti Devinder Sandhu Deepak Sidhu Kulvinder S. Gill 《Molecular breeding : new strategies in plant improvement》2010,26(2):177-187
Centromeric regions of higher eukaryotes are comprised mainly of tandem and non-tandem repeat sequences with variable copy
number, spacing, order and orientation; are heterochromatic in nature, and are believed to be devoid of actively transcribing
genes. Here, we report an actively transcribing wheat homolog of HSP70 gene that maps in the functional wheat centromere, and copy number of which seems to change in response to centromeric breaks.
The HSP70 gene physically maps on the short arm of chromosomes 1A and 1D of Chinese Spring (CS) and 1R of rye. Whereas, on chromosome 1B in both ‘CS’ and Pavon background, the gene maps in the functional centromere as evident from its presence in both cytologically
confirmed true ditelosomic lines Dt1BS and Dt1BL. Sequence comparison of 11 ESTs showed three sequence patterns suggesting
that all three homoeologous copies of the gene are expressing. The cDNA-single stranded conformation polymorphism analysis
confirmed expression of the ‘CS’ 1B copy of the gene. Observed in two independently developed Dt1BL lines, the 1B copy number of the gene showed three to fivefold increase in response to chromosomal breaks around the centromere. Putative
gene duplications seem to involve large chromosomal segments as only one of the ten restriction enzymes used for DNA gel-blot
analysis showed unique extra fragment band in the Dt1BL line. Further investigations are warranted to uncover the nature and
mechanism of these duplications. 相似文献
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