Environmental Factors Affecting the Release and Dispersal of Ascospores of Mycosphaerella citri     

Mondal SN  Gottwald TR  Timmer LW 《Phytopathology》2003,93(8):1031-1036

ABSTRACT Greasy spot, caused by Mycosphaerella citri, produces a leaf spot disease affecting all citrus species in Florida and the Caribbean Basin. M. citri produces pseudothecia and ascospores, which are considered the principal source of inoculum, in decomposing leaves on the grove floor. In studies using a computer-controlled environmental chamber, a single rain event triggered release of most mature ascospores beginning 30 to 60 min after the rain event. Additional rain events did not bring about further release. High relative humidity without rain triggered release of low numbers of ascospores, but vibration and red/infrared irradiation had little or no effect on ascospore release. After three to four cycles of wetting and drying of leaves, all pseudothecia had matured and released their ascospores. In the field, ascospores were detectable starting about 2 h after the beginning of a rain or irrigation and most ascospores were released within 16 h. Ascospore release was greatest following rain events and somewhat less following irrigations, and low numbers of ascospores were detectable on days without precipitation. Ascospore numbers declined linearly with horizontal distance from the source and as a function of the logarithm of ascospore numbers with vertical distance. Low numbers of ascospores were detected 7.5 m above the ground and 90 m downwind from the grove. Ascospore release can be advanced by irrigating frequently during dry, nonconducive conditions to stimulate ascospore release when environmental conditions are unfavorable for infection, but the eventual effects on disease severity are uncertain.  相似文献   

Environmental Factors Affecting Pseudothecial Development and Ascospore Production of Mycosphaerella citri, the Cause of Citrus Greasy Spot     

Mondal SN  Timmer LW 《Phytopathology》2002,92(12):1267-1275

ABSTRACT Mycosphaerella citri, the cause of citrus greasy spot, produces pseudothecia and ascospores in decomposing leaf litter on the grove floor. In laboratory studies, the effect of wetting and drying and temperature on the formation, maturation, and production of pseudothecia and ascospores was evaluated on mature, detached grapefruit leaves. Production of pseudothecia was most rapid when leaves were soaked five times per week for 2 h per day, but pseudothecial density and total ascospore production were greatest when leaves were soaked three times per week for 2 h per day. In duration of wetting studies, 3 h per day, 3 days per week brought about the most rapid production, but 10 to 30 min per day resulted in production of the most pseudothecia and ascospores. Pseudothecia and ascospore production were greatest at 28 degrees C and declined rapidly at lower and higher temperatures. Maturation of pseudothecia was slow at 20 and 24 degrees C, but production was high at 24 degrees C; at 32 degrees C, pseudothecia matured rapidly, but degenerated quickly. No mature pseudothecia were produced on leaves maintained continuously under wet conditions. In field studies, leaves were placed on the grove floor monthly from April 2000 to September 2001. Pseudothecia production was rapid during the summer rainy season from June to September. Pseudothecia produced on leaves placed in the grove from October to May developed and matured more slowly but were produced in much larger numbers than in summer. The number of days to first pseudothecial initials, 50% maturation, first discharge of ascospores, leaf decomposition, as well as pseudothecial density and incidence, were negatively related to average temperature. Total ascospore production was unrelated to temperature.  相似文献   

Effect of Planting Geometry on the Growth and Yield Performance of Maize Intercropped with Rice     

Ashratun  Nesa  A. Hamid    M. H. Mondal  A. F. M. Maniruzzaman 《Journal of Agronomy and Crop Science》1989,162(3):166-171

A field experiment with maize and rice planted under four planting configurations in an intercropping system was conducted to evaluate the plant competition effects on the performance of component crops. Intercropping substantially reduced grain yields of both rice and maize. Rice yield was generally low giving monocrop yield of 1,084 kg/ha. Intercropped rice ranged between 179 kg/ha and 615 kg/ha depending on maize planting arrangement. Monocrop maize yielded highest in square planting (3,617 kg/ha) and lowest in skip-row (2,600 kg/ha) planting, but planting geometry did not influence intercropped maize yield. Monocrop maize outyielded the combined yield of component crops suggesting no yield advantage through rice-maize intercropping.  相似文献   

Effects of temperature and pH on the osmotic fragility of erythrocytes of yaks     

Sarkar M  Mondal DB  Mohanty TK  Pal RN 《Australian veterinary journal》1999,77(3):188-189

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Isolation and characterization of two lytic bacteriophages against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> from India: newer therapeutic agents against Bovine mastitis     

M. Y. Ganaie  S. Qureshi  Z. Kashoo  S. A. Wani  M. I. Hussain  R. Kumar  R. Maqbool  P. Sikander  M. S. Banday  W. A. Malla  P. Mondal  R. I. N. Khan 《Veterinary research communications》2018,42(4):289-295

Bovine mastitis causes severe economic losses to dairy farmers. Staphylococcus aureus, is one of the most important pathogen implicated in etiology of clinical and subclinical mastitis in bovines. In view of increasing antimicrobial resistance alternatives to antibiotic therapy are much needed. The present decade has witnessed a renewed interest in phage based therapeutics and diagnostics. The present study, describes isolation and characterization of two lytic phages SAJK-IND and MSP against Staphylococcus aureus having a potential to be used in therapy against mastitis. SAJK-IND and MSP phages belonged to Myoviridae and Podoviridae families, respectively. TEM imaging of the two phages revealed an iscosahedral head. MSP phage has a short non contractile tail. SAJK-IND and MSP have a burst size of 44?±?3 and 25?±?5 PFU/ infected cell, respectively. SAJK-IND and MSP phages revealed ? 12 and ?16 proteins, respectively on SDS-PAGE analysis. The lytic activity of the phages was specific for Staphylococcus aureus. SAJK-IND revealed 100% lytic activity against several strains of Staphylococcus aureus isolated from mastitis milk samples whereas, MSP had only 40% lytic activity. SAJK-IND phage genome was sequenced, assembled and deposited in Genbank under accession no MG010123.  相似文献   

Molecular characterization of a poxvirus isolated from an American flamingo (Phoeniconais ruber rubber)     

Mondal SP  Lucio-Martínez B  Buckles EL 《Avian diseases》2008,52(3):520-525

An avian poxvirus from the beak scab of an American flamingo (Phoeniconais ruber rubber) was isolated by inoculation on the chorioallantoic membrane (CAM) of specific-pathogen-free (SPF) chicken embryos. The virus produced multifocal areas of epithelial hyperplasia along with foci of inflammation in the CAM, and rare cells contained small eosinophilic intracytoplasmic bodies. Chickens inoculated with the isolated virus in the feather follicle of the leg did not develop significant lesions. Nucleotide sequence comparison of a PCR-amplified 4.5 kb HindIII fragment of the genome of flamingo poxvirus (FlPV) revealed very high homology (99.7%) with condor poxvirus (CPV), followed by approximately 92% similarity with canary poxvirus (CNPV) and Hawaiian goose poxvirus (HGPV), but less similarity (approximately 69%) to fowl poxvirus (FPV), the type species of the genus Avipoxvirus of family Poxviridae. As in the cases with CPV, CNPV, and HGPV, genetic analysis of FlPV revealed an absence of three corresponding FPV open reading frames (ORF199, 200, and 202) and an absence of any reticuloendotheliosis virus (REV) sequences in this region. There are only nine nucleotide substitutions observed between FlPV and CPV in the 4.5 kb fragment; those were clustered in the ORF201 region, which in FPV genome is a site for integration of REV sequences. Phylogenetic analysis of the predicted amino acid sequences of the ORF201-coded hypothetical protein demonstrated FlPV to be more closely related to CPV, as well as to CNPV and HGPV, than to FPV.  相似文献   

Relationship between peripheral plasma inhibin and FSH concentrations in Sahiwal cows (<Emphasis Type="Italic">Bos indicus</Emphasis>) and Murrah buffaloes (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) during estrous cycle     

Mondal S  Prakash BS  Palta P 《Tropical animal health and production》2008,40(6):403-406

The present investigation was undertaken to study the relationship between circulating inhibin and FSH concentrations during the estrous cycle in buffaloes and Sahiwal cattle. The pattern of inhibin concentrations was similar, with peak concentrations on Day -2 (Day 0 = day of estrus) and minimum concentrations on Days 12 and 11 in buffaloes and cattle, respectively. Circulating FSH concentrations were the highest on Day 0 and lowest on Days 8 and 13 in buffaloes and cattle, respectively. Peripheral plasma inhibin concentrations were negatively correlated to FSH concentrations in buffaloes (r = -0.27, P < 0.01) and cattle (r = -0.35, P < 0.01) indicating that inhibin is involved in negative feedback regulation of FSH in both these species.  相似文献   

An Update on Reproduction in Yak and Mithun     

BS Prakash  M Sarkar  M Mondal 《Reproduction in domestic animals》2008,43(S2):217-223

Yak and mithun are two domesticated herbivores of high economic importance to the farming community living in highlands. Improved yak and mithun production could significantly enhance the living standards of these highlanders. Over the years, their dwindling numbers have been a cause of serious concern. In view of the lack of knowledge on the reproductive physiology of these ruminants, studies have been undertaken to investigate their reproductive endocrinology in recent years. This paper attempts to present the latest information on the endocrine changes associated with their various reproductive processes viz. growth and puberty, oestrous cyclicity and oestrous behaviour, ovulation, and, pregnancy and parturition. The paper also provides the recent developments on research done towards the enhancement of yak and mithun reproductive efficiencies through endocrine and embryo biotechniques.  相似文献   

Genomic resources for breeding crops with enhanced abiotic stress tolerance     

Kailash C. Bansal  Sangram K. Lenka  Tapan K. Mondal 《Plant Breeding》2014,133(1):1-11

To meet the challenges of climate change, exploring natural diversity in the existing plant genetic resource pool as well as creation of new mutants through chemical mutagenesis and molecular biology is needed for developing climate‐resilient elite genotypes. Ever‐increasing area under existing abiotic stresses as well as emerging abiotic stress factors and their combinations have further added to the problems of the current crop improvement programmes. However, with the advancement in modern techniques such as next‐generation sequencing technologies, it is now possible to generate on a whole‐genome scale, genomic resources for crop species at a much faster pace with considerably less efforts and money. The genomic resources thus generated will be useful for various plant breeding applications such as marker‐assisted breeding for gene introgression, mapping QTLs or identifying new or rare alleles associated with a particular trait. In this article, we discuss various aspects of generation of genomic resources and their utilization for developing abiotic stress‐tolerant crops to ensure sustainable agricultural production and food security in the backdrop of rapid climate change.  相似文献   

Molecular diversity and association of SSR markers to rust and late leaf spot resistance in cultivated groundnut (Arachis hypogaea L.)     

S. Mondal    A. M. Badigannavar 《Plant Breeding》2010,129(1):68-71

Molecular diversity and association of simple sequence repeat (SSR) markers with rust and late leaf spot (LLS) resistance were detected in a set of 20 cultivated groundnut genotypes differing in resistance against both diseases. Out of 136 bands amplified from 26 primers, 104 were found polymorphic (76.5%). Cluster analysis (UPGMA) revealed two main clusters separated at 52% Jaccard's similarity coefficient according to disease reaction to rust and LLS. Based on the Kruskal–Wallis one-way anova and simple regression analysis three and four SSR alleles were found associated with rust and LLS resistance, respectively.  相似文献