Physiological and biophysical alterations in maize plants caused by Colletotrichum graminicola infection verified by OJIP study

Plant growth promoting endophytic bacteria, which can fix nitrogen, plays a vital role in plant growth promotion. Previous authors have evaluated the effect of Gluconacetobacter diazotrophicus Pal5 inoculation on plants subjected to different sources of abiotic stress on an individual basis. The present study aimed to appraise the effect of G. diazotrophicus inoculation on the amelioration of the individual and combined effects of drought and nitrogen stress in maize plants (Zea mays L.). A pot experiment was conducted whereby treatments consisted of maize plants cultivated under drought stress, in soil with a low nitrogen concentration and these two stress sources combined, with and without G. diazotrophicus seed inoculation. The inoculated plants showed increased plant biomass, chlorophyll content, plant nitrogen uptake, and water use efficiency. A general increase in copy numbers of G. diazotrophicus, based on 16S rRNA gene quantification, was detected under combined moderate stress, in addition to an increase in the abundance of genes involved in N fixation (nifH). Endophytic colonization of bacteria was negatively affected by severe stress treatments. Overall, G. diazotrophicus Pal5 can be considered as an effective tool to increase maize crop production under drought conditions with low application of nitrogen fertilizer.

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Silicon Supplied Via Roots or Leaves Relieves Potassium Deficiency in Maize Plants

Silicon ◽

10.1007/s12633-020-00908-1 ◽

2021 ◽

Author(s):

Marcilene Machado dos Santos Sarah ◽

Renato de Mello Prado ◽

Gelza Carliane Marques Teixeira ◽

Jonas Pereira de Souza Júnior ◽

Robson Luis Silva de Medeiros ◽

...

Keyword(s):

Potassium Deficiency ◽

Maize Plants

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Assessment of physiological races of Exserohilum turcicum isolates from maize in Argentina and Brazil

Tropical Plant Pathology ◽

10.1007/s40858-020-00417-x ◽

2021 ◽

Author(s):

Barbara Ludwig Navarro ◽

Lucia Ramos Romero ◽

María Belén Kistner ◽

Juliana Iglesias ◽

Andreas von Tiedemann

Keyword(s):

Exserohilum Turcicum ◽

Breeding Programs ◽

Physiological Races ◽

Maize Leaves ◽

Race 1 ◽

Resistance Reaction ◽

Qualitative Resistance ◽

Maize Plants ◽

Corn Leaf Blight ◽

Resistant Genotypes

AbstractNorthern corn leaf blight (NCLB) is one of the most important diseases in maize worldwide. It is caused by the fungus Exserohilum turcicum, which exhibits a high genetic variability for virulence, and hence physiological races have been reported. Disease control is based mainly on fungicide application and host resistance. Qualitative resistance has been widely used to control NCLB through the deployment of Ht genes. Known pathogen races are designated according to their virulence to the corresponding Ht gene. Knowledge about of E. turcicum race distribution in maize-producing areas is essential to develop and exploit resistant genotypes. Maize leaves showing distinct elliptical grey-green lesions were collected from maize-producing areas of Argentina and Brazil, and 184 monosporic E. turcicum isolates were obtained. A total of 66 isolates were collected from Argentina during 2015, 2018 and 2019, while 118 isolates from Brazil were collected during 2017, 2018 and 2019. All isolates were screened on maize differential lines containing Ht1, Ht2, Ht3 and Htn1 resistance genes. In greenhouse experiments, inoculated maize plants were evaluated at 14 days after inoculation. Resistance reaction was characterized by chlorosis, and susceptibility was defined by necrosis in the absence of chlorosis. The most frequent race was 0 in both Argentina (83%) and Brazil (65%). Frequencies of race 1 (6% and 24%) and race 23N (5% and 10%) were very low in Argentina and Brazil, respectively. The high frequency of race 0 isolates provides evidence that qualitative resistance based on the tested Ht genes is not being used extensively in Argentina and Brazil to control NCLB. This information may be relevant for growers and breeding programs as the incidence of NCLB is increasing in both countries.

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Isolation and Characterization of Fungal Endophytes Isolated from Medicinal Plant Ephedra pachyclada as Plant Growth-Promoting

Biomolecules ◽

10.3390/biom11020140 ◽

2021 ◽

Vol 11 (2) ◽

pp. 140 ◽

Cited By ~ 2

Author(s):

Ahmed Mohamed Aly Khalil ◽

Saad El-Din Hassan ◽

Sultan M. Alsharif ◽

Ahmed M. Eid ◽

Emad El-Din Ewais ◽

...

Keyword(s):

Medicinal Plants ◽

Plant Growth ◽

Aspergillus Flavus ◽

Endophytic Fungi ◽

Fungal Endophytes ◽

Penicillium Crustosum ◽

Plant Growth Promoting ◽

Penicillium Commune ◽

Maize Plants ◽

Growth Promoting

Endophytic fungi are widely present in internal plant tissues and provide different benefits to their host. Medicinal plants have unexplored diversity of functional fungal association; therefore, this study aimed to isolate endophytic fungi associated with leaves of medicinal plants Ephedra pachyclada and evaluate their plant growth-promoting properties. Fifteen isolated fungal endophytes belonging to Ascomycota, with three different genera, Penicillium, Alternaria, and Aspergillus, were obtained from healthy leaves of E. pachyclada. These fungal endophytes have varied antimicrobial activity against human pathogenic microbes and produce ammonia and indole acetic acid (IAA), in addition to their enzymatic activity. The results showed that Penicillium commune EP-5 had a maximum IAA productivity of 192.1 ± 4.04 µg mL−1 in the presence of 5 µg mL−1 tryptophan. The fungal isolates of Penicillium crustosum EP-2, Penicillium chrysogenum EP-3, and Aspergillus flavus EP-14 exhibited variable efficiency for solubilizing phosphate salts. Five representative fungal endophytes of Penicillium crustosum EP-2, Penicillium commune EP-5, Penicillium caseifulvum EP-11, Alternaria tenuissima EP-13, and Aspergillus flavus EP-14 and their consortium were selected and applied as bioinoculant to maize plants. The results showed that Penicillium commune EP-5 increased root lengths from 15.8 ± 0.8 to 22.1 ± 0.6. Moreover, the vegetative growth features of inoculated maize plants improved more than the uninoculated ones.

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