Bioprospecting biofilm-forming epiphytic bacteria from wheat under oligotrophic conditions.

Abstract: Naturally occurring epiphytic microorganisms display different colonization strategies. Studies report their potential in acting as biocontrol agents through several mechanisms such as competition for space and nutrients, production of antibiotics, resistance induction, parasitism, among others. However, little is known about the mechanisms that could possibly act in the control of the pathogenic fungus Magnaporthe grisea, responsible for wheat blast. Thus, the present work aimed the selection of epiphytic bacteria with the potential to act as biological control agents against M. grisea through different mechanisms of action. Bacterial isolates were subjected to direct antagonism tests. The growth rate in oligotrophic conditions (1% sucrose and 1% glucose) after 14 and 36 hours, biofilm production on 1% glucose and 1% sucrose and production of indole-3-acetic acid (IAA) were also tested. Thirty bacterial strains were isolated from wheat leaves (variety IAC 385) obtained from a field in Palmital, São Paulo state, Brazil. Any isolate showed direct antagonistic activity, indicating that no inhibition occurs through antibiosis. After 14 hours of growth, two strains (2EPPE3 and 1LCR10) exhibited better growth rate in medium supplemented with 1% sucrose. Biofilm production was favoured in one strain (1LCR3). More than 50 ?g.mL-1 of IAA was detected in one strain (1L10) and the production of this hormone might be related to the induction of defence response in plants. Isolates displaying the best growth rate in oligotrophic conditions and production of different compounds may be used together targeting a better biological control response against the plant pathogen. However, further analyses are necessary for verification of such mechanisms of action

Inorganic Chemical Fertilizer Application to Wheat Reduces the Abundance of Putative Plant Growth-Promoting Rhizobacteria

The profound negative effect of inorganic chemical fertilizer application on rhizobacterial diversity has been well documented using 16S rRNA gene amplicon sequencing and predictive metagenomics. We aimed to measure the function and relative abundance of readily culturable putative plant growth-promoting rhizobacterial (PGPR) isolates from wheat root soil samples under contrasting inorganic fertilization regimes. We hypothesized that putative PGPR abundance will be reduced in fertilized relative to unfertilized samples. Triticum aestivum cv. Cadenza seeds were sown in a nutrient depleted agricultural soil in pots treated with and without Osmocote⃝R fertilizer containing nitrogen-phosphorous-potassium (NPK). Rhizosphere and rhizoplane samples were collected at flowering stage (10 weeks) and analyzed by culture-independent (CI) amplicon sequence variant (ASV) analysis of rhizobacterial DNA as well as culture- dependent (CD) techniques. Rhizosphere and rhizoplane derived microbiota culture collections were tested for plant growth-promoting traits using functional bioassays. In general, fertilizer addition decreased the proportion of nutrient-solubilizing bacteria (nitrate, phosphate, potassium, iron, and zinc) isolated from rhizocompartments in wheat whereas salt tolerant bacteria were not affected. A “PGPR” database was created from isolate 16S rRNA gene sequences against which total amplified 16S rRNA soil DNA was searched, identifying 1.52% of total community ASVs as culturable PGPR isolates. Bioassays identified a higher proportion of PGPR in non-fertilized samples [rhizosphere (49%) and rhizoplane (91%)] compared to fertilized samples [rhizosphere (21%) and rhizoplane (19%)] which constituted approximately 1.95 and 1.25% in non-fertilized and fertilized total community DNA, respectively. The analyses of 16S rRNA genes and deduced functional profiles provide an in-depth understanding of the responses of bacterial communities to fertilizer; our study suggests that rhizobacteria that potentially benefit plants by mobilizing insoluble nutrients in soil are reduced by chemical fertilizer addition. This knowledge will benefit the development of more targeted biofertilization strategies

Bacterial structure of agricultural soils with high and low yields.

The purpose of this study was to evaluate the structure of bacterial communities at two agricultural fields in Brazil (Paraná (PR) and Bahia (BA) states) with a history of high and low productivity of soybean. 16S rRNA gene amplicons revealed that plots with low yield of grains showed greater bacterial richness than plots with high yield. The phylum Acidobacteria was more abundant in soil samples from PR site. The rhizosphere of plants presented a similar bacterial community for both high and low yield plots. Soil samples from BA showed differences in the diversity between the plots with high and low productivity. The use of 16S rRNA amplicon sequencing allowed the assessment of differences between plots with different soybean yields. This might be useful in the future to harness plant microbiomes for increased crop productivity

Potencial de micro-organismos rizosféricos no controle do fitopatógeno Magnaporthe grisea "in vitro".

Resumo: A cultura do trigo, no Brasil e em alguns países do mundo, tem sido afetada economicamente pela presença de fungos causadores de doenças, como no caso em estudo, o fitopatógeno Magnaporthe grisea, causador da brusone. Representa um dos mais sérios problemas para a produção de trigo no Brasil, afetando cerca de 60% da cultura, com inúmeras perdas na produtividade. Visando avaliar o potencial de bactérias presentes na rizosfera de trigo cultivado em diferentes locais em inibir Magnaporthe grisea em placas de Petri, um total de 313 bactérias e actinobactérias foram isoladas. Cerca de 36% apresentou potencial antagonista, sendo 18%, a maior porcentagem, de Palmital-SP, onde não havia indícios da doença. Os resultados sugerem que algumas bactérias presentes na rizosfera de trigo apresentam potencial antagonista ao fungo M. grisea. Isto pode contribuir para o controle biológico da brusone do trigo de uma maneira que resulte em menos impactos ao meio ambiente. Resumo: Wheat crop in Brazil and in some countries of the world, has been economically affected by the presence of fungi which cause diseases such as the plant pathogen Magnaporthe grisea, causing wheat blast. It is one of the most serious problems for wheat production in Brazil, affecting about 60% of crop with several losses in productivity. To evaluate the potential of bacteria present in the rhizosphere of wheat grown in different sites in inhibiting M. grisea on Petri dishes, a total of 313 bacteria and actinobacteria were isolated. About 36% displayed antagonism, with 18%, the highest percentage belonging to the site of Palmital-SP, where there was no evidence of disease. The results suggest some bacteria present in wheat rhizosphere have antagonist potential against the fungus M. grisea. This may contribute to the biological control of wheat blast in a manner that results in less impact on the environment

Cardio-Facio-Cutaneous Syndrome: Clinical Features, Diagnosis, and Management Guidelines

Cardio-facio-cutaneous syndrome (CFC) is one of the RASopathies that bears many clinical features in common with the other syndromes in this group, most notably Noonan syndrome and Costello syndrome. CFC is genetically heterogeneous and caused by gene mutations in the Ras/mitogen-activated protein kinase pathway. the major features of CFC include characteristic craniofacial dysmorphology, congenital heart disease, dermatologic abnormalities, growth retardation, and intellectual disability. It is essential that this condition be differentiated from other RASopathies, as a correct diagnosis is important for appropriate medical management and determining recurrence risk. Children and adults with CFC require multidisciplinary care from specialists, and the need for comprehensive management has been apparent to families and health care professionals caring for affected individuals. To address this need, CFC International, a nonprofit family support organization that provides a forum for information, support, and facilitation of research in basic medical and social issues affecting individuals with CFC, organized a consensus conference. Experts in multiple medical specialties provided clinical management guidelines for pediatricians and other care providers. These guidelines will assist in an accurate diagnosis of individuals with CFC, provide best practice recommendations, and facilitate long-term medical care.CFC International, Vestal, New YorkNational Institutes of HealthNational Institutes of Health (NIH)Univ Minnesota, Dept Pediat & Ophthalmol, Div Genet & Metab, Minneapolis, MN 55454 USAUniv Minnesota, Dept Pediat, Div Clin Behav Neuroscience, Minneapolis, MN 55454 USAChildrens Hosp & Clin Minnesota, St Paul, MN USATexas Childrens Hosp, Dept Mol & Human Genet, Houston, TX 77030 USABaylor Coll Med, Houston, TX 77030 USABenioff Childrens Hosp, Madison Clin Pediat Diabet, San Francisco, CA USAUniv Calif San Francisco, San Francisco, CA 94143 USAUniversidade Federal de São Paulo, Med Genet Ctr, São Paulo, BrazilCatholic Univ, A Gemelli Sch Med, Inst Med Genet, Rome, ItalyUniv Kentucky, Dept Pediat, Lexington, KY USAUniv Texas Hlth Sci Ctr San Antonio, Dept Orthoped, San Antonio, TX 78229 USABoston Childrens Hosp, Dept Cardiol, Boston, MA USABoston Childrens Hosp, Div Genet, Boston, MA USAHarvard Univ, Sch Med, Boston, MA USAEmory Univ, Sch Med, Dept Human Genet, Atlanta, GA USAEmory Univ, Sch Med, Dept Ophthalmol, Atlanta, GA 30322 USAUniv Calif San Francisco, Dept Neurol, San Francisco, CA USAYoungstown State Univ, Special Educ & Sch Psychol, Dept Counseling, Youngstown, OH 44555 USACFC Int, Vestal, NY USAUniv Calif Davis, UC Davis MIND Inst, Dept Pediat, Div Genom Med, Sacramento, CA 95817 USAUniversidade Federal de São Paulo, Med Genet Ctr, São Paulo, BrazilNational Institutes of Health: R01-AR062165Web of Scienc

Noonan syndrome and related disorders: Alterations in growth and puberty

Noonan syndrome is a relatively common multiple malformation syndrome with characteristic facies, short stature and congenital heart disease, most commonly pulmonary stenosis (Noonan, Clin Pediatr, 33:548–555, 1994). Recently, a mutation in the PTPN11 gene (Tartaglia, Mehler, Goldberg, Zampino, Brunner, Kremer et al., Nat Genet, 29:465–468, 2001) was found to be present in about 50% of individuals with Noonan syndrome. The phenotype noted in Noonan syndrome is also found in a number of other syndromes which include LEOPARD (Gorlin, Anderson, Blaw, Am J Dis Child, 17:652–662, 1969), Cardio-facio-cutaneous syndrome (Reynolds, Neri, Hermann, Blumberg, Coldwell, Miles et al., Am J Med Genet, 28:413–427, 1986) and Costello syndrome (Hennekam, Am J Med Genet, 117C(1):42–48, 2003). All three of these syndromes share similar cardiac defects and all have postnatal short stature. Very recently, HRAS mutations (Aoki, Niihori, Kawame, Kurosawa, Ohashi, Tanaka et al., Nat Genet, 37:1038–1040, 2005) have been found in the Costello syndrome and germline mutations in KRAS and BRAF genes (Rodriguez-Viciana, Tetsu, Tidyman, Estep, Conger, Santa Cruz et al., Nat Genet,2006; Niihori, Aoki, Narumi, Neri, Cave, Verloes et al., Nat Genet, 38:294–296, 2006) in the Cardio-facio-cutaneous syndrome. Phenotypic overlap between these genetic disorders can now be explained since each is caused by germline mutations that are major components of the RAS-MAPK pathway. This pathway plays an important role in growth factor and cytokine signaling as well as cancer pathogenesis