A Manual of Soil Fungi

Inoculation with Pseudomonas spp. Containing ACC-Deaminase Partially Eliminates the Effects of Drought Stress on Growth, Yield, and Ripening of Pea (Pisum sativum L.)

A series of experiments were conducted to assess the effectiveness of rhizobacteria containing 1-aminocyclopropane- 1-carboxylate (ACC) deaminase for growth promotion of peas under drought conditions. Ten rhizobacteria isolated from the rhizosphere of different crops (peas, wheat, and maize) were screened for their growth promoting ability in peas under axenic condition. Three rhizobacterial isolates, Pseudomonas fluorescens biotype G (ACC-5), P. fluorescens (ACC-14), and P. putida biotype A (Q-7), were selected for pot trial on the basis of their source, ACC deaminase activity, root colonization, and growth promoting activity under axenic conditions. Inoculated and uninoculated (control) seeds of pea cultivar 2000 were sown in pots (4 seeds/pot) at different soil moisture levels (25, 50, 75, and 100% of field capacity). Results revealed that decreasing the soil moisture levels from 100 to 25% of field capacity significantly decreased the growth of peas. However, inoculation of peas with rhizobacteria containing ACC deaminase significantly decreased the "drought stress imposed effects" on growth of peas, although with variable efficacy at different moisture levels. At the lowest soil moisture level (25% field capacity), rhizobacterial isolate Pseudomonas fluorescens biotype G (ACC-5) was found to be more promising compared with the other isolates, as it caused maximum increases in fresh weight, dry weight, root length, shoot length, number of leaves per plant, and water use efficiency on fresh and dry weight basis (45, 150, 92, 45, 140, 46, and 147%, respectively) compared with respective uninoculated controls. It is highly likely that rhizobacteria containing ACC deaminase might have decreased the drought-stress induced ethylene in inoculated plants, which resulted in better growth of plants even at low moisture levels. Therefore, inoculation with rhizobacteria containing ACC deaminase could be helpful in eliminating the inhibitory effects of drought stress on the growth of peas.

https://www.koreascience.or.kr:443/article/JAKO200822179194535.pdf

Effectiveness of rhizobacteria containing ACC deaminase for growth promotion of peas (Pisum sativum) under drought conditions.

Fusarium head blight (FHB) is an important disease principally attacking wheat, barley and other grains worldwide. Among the Fusarium species causing this disease, the most common is Fusarium graminearum. F. avenaceum, F. culmorum and F. poae are also responsible for FHB, but are less often implicated. F. poae is a fungus of increasingly recognized importance, which has been associated with human and animal toxicoses as its strains produce aurofusarin, beauvericin, butenolide, culmorin, cyclonerodiol, enniatins, fusarin, moniliformin, and trichothecenes of types A and B. The extensive range of mycotoxin production of this fungus requires particular attention because of the toxicological problems it may elicit. Moreover, as the profiles of grain contaminants caused by FHB seem to be related to different environmental conditions, multiple evaluations using data collected from a large range of sites with different climatic conditions, would be extremely useful. The aim of the present review is to highlight the importance of F. poae in the FHB complex.

Fusarium poae: a pathogen that needs more attention.

Fusarium head blight (FHB), or scab, for its devastating nature to wheat production and food security, has stimulated worldwide attention. Multidisciplinary efforts have been made to fight against FHB for a long time, but the great progress has been achieved only in the genomics era of the past 20 years, particularly in the areas of resistance gene/QTL discovery, resistance mechanism elucidation and molecular breeding for better resistance. This review includes the following nine main sections, (1) FHB incidence, epidemic and impact, (2) causal Fusarium species, distribution and virulence, (3) types of host resistance to FHB, (4) germplasm exploitation for FHB resistance, (5) genetic control of FHB resistance, (6) fine mapping of Fhb1, Fhb2, Fhb4 and Fhb5, (7) cloning of Fhb1, (8) omics-based gene discovery and resistance mechanism study and (9) breeding for better FHB resistance. The advancements that have been made are outstanding and exciting; however, judged by the complicated nature of resistance to hemi-biotrophic pathogens like Fusarium species and lack of immune germplasm, it is still a long way to go to overcome FHB.

https://link.springer.com/content/pdf/10.1007/s00122-019-03525-8.pdf

Germplasms, genetics and genomics for better control of disastrous wheat Fusarium head blight.

PCR approach based on the esyn1 gene for the detection of potential enniatin-producing Fusarium species

The effect of water stress on wheat kernel size, color and protein composition

In a three-year field experiment the assessment of leaves and ears photosynthesis rate in spring wheat was made using a LI-COR 6400 portable photosynthesis system. The photosynthetic rate of spring wheat was affected by cultivars, nitrogen fertilization and weather conditions. We generally found a negative correlation between the yield of spring wheat and the rate of photosynthesis in flag leaves in phases 39–55 BBCH (the strength of this ef fect depended on the level of nitrogen fertilization). Strong negative correlation occurred for cv. Bryza in phases: 39–51 BBCH in treatment fertilized with lower dose of nitrogen and in phase 39–41 BBCH for dose 120 kg/ha. There was a significant negative correlation for cv. Tybald only in phase 39–41 BBCH for higher dose of nitrogen and 52–55 BBCH for lower dose. Our studies show that the photosynthetic activity of flag leaves decreased from the booting (39–41 BBCH) to heading stage (52–55 BBCH), and their function was taken over by ears. Contrary to flag leaf, in wheat ears the intensity of photosynthesis correlated positively with grain yield for most of the studied period (52–65 BBCH, with highly significant correlation at 56–57 BBCH and – only for high nitrogen treatments – at 59–61 BBCH; a negative correlation was generally observed at a later phase, i.e. at 65–69 BBCH). Contrary to flag leaf pho tosynthesis, the intensity of this process in wheat ears (at the heading and flowering stages) seems highly relevant for grain yield. High positive correlation was noted in 56–57 BBCH and 61–65 BBCH. However, the study was done in field conditions and for definitive conclusions observations over a longer period would be desirable.

/pdf/the-effect-of-nitrogen-fertilization-on-flag-leaf-and-ear-2va2quxgje.pdf

The effect of nitrogen fertilization on flag leaf and ear photosynthesis and grain yield of spring wheat.

Fusarium head blight (FHB) of cereals is the major head disease negatively affecting grain production worldwide. In 2016 and 2017, serious outbreaks of FHB occurred in wheat crops in Poland. In this study, we characterized the diversity of Fusaria responsible for these epidemics using TaqMan assays. From a panel of 463 field isolates collected from wheat, four Fusarium species were identified. The predominant species were F. graminearum s.s. (81%) and, to a lesser extent, F. avenaceum (15%). The emergence of the 15ADON genotype was found ranging from 83% to 87% of the total trichothecene genotypes isolated in 2016 and 2017, respectively. Our results indicate two dramatic shifts within fungal field populations in Poland. The first shift is associated with the displacement of F. culmorum by F. graminearum s.s. The second shift resulted from a loss of nivalenol genotypes. We suggest that an emerging prevalence of F. graminearum s.s. may be linked to boosted maize production, which has increased substantially over the last decade in Poland. To detect variation within Tri core clusters, we compared sequence data from randomly selected field isolates with a panel of strains from geographically diverse origins. We found that the newly emerged 15ADON genotypes do not exhibit a specific pattern of polymorphism enabling their clear differentiation from the other European strains.

Jacek Olszewski

Papers

PCR approach based on the esyn1 gene for the detection of potential enniatin-producing Fusarium species

The effect of water stress on wheat kernel size, color and protein composition

The effect of nitrogen fertilization on flag leaf and ear photosynthesis and grain yield of spring wheat.

Species Composition and Trichothecene Genotype Profiling of Fusarium Field Isolates Recovered from Wheat in Poland.

Rate of photosynthesis and transpiration of winter wheat leaves and ears under water deficit conditions