scholarly journals Metabolic Potential of Epichloë Endophytes for Host Grass Fungal Disease Resistance

2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Krishni Fernando ◽  
Priyanka Reddy ◽  
German C. Spangenberg ◽  
Simone J. Rochfort ◽  
Kathryn M. Guthridge

Asexual species of the genus Epichloë (Clavicipitaceae, Ascomycota) form endosymbiotic associations with Pooidae grasses. This association is important both ecologically and to the pasture and turf industries, as the endophytic fungi confer a multitude of benefits to their host plant that improve competitive ability and performance such as growth promotion, abiotic stress tolerance, pest deterrence and increased host disease resistance. Biotic stress tolerance conferred by the production of bioprotective metabolites has a critical role in an industry context. While the known antimammalian and insecticidal toxins are well characterized due to their impact on livestock welfare, antimicrobial metabolites are less studied. Both pasture and turf grasses are challenged by many phytopathogenic diseases that result in significant economic losses and impact livestock health. Further investigations of Epichloë endophytes as natural biocontrol agents can be conducted on strains that are safe for animals. With the additional benefits of possessing host disease resistance, these strains would increase their commercial importance. Field reports have indicated that pasture grasses associated with Epichloë endophytes are superior in resisting fungal pathogens. However, only a few antifungal compounds have been identified and chemically characterized, and these from sexual (pathogenic) Epichloë species, rather than those utilized to enhance performance in turf and pasture industries. This review provides insight into the various strategies reported in identifying antifungal activity from Epichloë endophytes and, where described, the associated antifungal metabolites responsible for the activity.

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10206
Author(s):  
Juanjuan Huang ◽  
Shengji Wang ◽  
Xingdou Wang ◽  
Yan Fan ◽  
Youzhi Han

Ethylene response factors (ERFs) are plant-specific transcription factors (TFs) that play important roles in plant growth and stress defense and have received a great amount of attention in recent years. In this study, seven ERF genes related to abiotic stress tolerance and response were identified in plants of the Populus genus. Systematic bioinformatics, including sequence phylogeny, genome organisation, gene structure, gene ontology (GO) annotation, etc. were detected. Expression-pattern of these seven ERF genes were analyzed using RT-qPCR and cross validated using RNA-Seq. Data from a phylogenetic tree and multiple alignment of protein sequences indicated that these seven ERF TFs belong to three subfamilies and contain AP2, YRG, and RAYD conserved domains, which may interact with downstream target genes to regulate the plant stress response. An analysis of the structure and promoter region of these seven ERF genes showed that they have multiple stress-related motifs and cis-elements, which may play roles in the plant stress-tolerance process through a transcriptional regulation mechanism; moreover, the cellular_component and molecular_function terms associated with these ERFs determined by GO annotation supported this hypothesis. In addition, the spatio-temporal expression pattern of these seven ERFs, as detected using RT-qPCR and RNA-seq, suggested that they play a critical role in mediating the salt response and tolerance in a dynamic and tissue-specific manner. The results of this study provide a solid basis to explore the functions of the stress-related ERF TFs in Populus abiotic stress tolerance and development process.


Agriculture ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 425
Author(s):  
Elisa Pasquali ◽  
Gianni Barcaccia

Flowering time, abiotic stress tolerance and disease resistance are important agronomic traits of forage species like Lolium spp. Understanding the genetic control of these traits is enabled by the combination of genomic tools with conventional breeding techniques. Flowering time in this genus represents a complex trait due to the differences in the primary induction requirements among the species. In total, 36 QTLs (Quantitative Trait Locus) were identified across all seven linkage groups of Italian and perennial ryegrass involved in the flowering pathways, with several putative orthologous/homologous genes that have been characterized in other major crops. From the perspective of climate change, abiotic stress tolerance has become an essential feature; many QTLs that are involved in the control of plant responses have been identified, and transcriptional studies focusing on drought tolerance reported several DEGs (Differentially Expressed Genes) involved in carbon and lipid metabolism and signal transduction. Due to the incidence of microbial diseases, QTLs useful to developing cultivars resistant to bacterial wilt (Xanthomonas translucens pv. graminis), ryegrass crown rust (Puccinia coronata f. sp. Lolii) and gray leaf spot (Magnaporthe grisea/oryzae) have been mapped in both L. perenne and L. multiflorum populations. Due to the great importance of Lolium species, especially as forage crops, additional information about the three aforementioned agronomic traits is needed.


2020 ◽  
Vol 11 ◽  
Author(s):  
P. B. Kavi Kishor ◽  
Renuka Suravajhala ◽  
Guddimalli Rajasheker ◽  
Nagaraju Marka ◽  
Kondle Kavya Shridhar ◽  
...  

Lysine (Lys) is indispensable nutritionally, and its levels in plants are modulated by both transcriptional and post-transcriptional control during plant ontogeny. Animal glutamate receptor homologs have been detected in plants, which may participate in several plant processes through the Lys catabolic products. Interestingly, a connection between Lys and serotonin metabolism has been established recently in rice. 2-Aminoadipate, a catabolic product of Lys appears to play a critical role between serotonin accumulation and the color of rice endosperm/grain. It has also been shown that expression of some lysine-methylated proteins and genes encoding lysine-methyltransferases (KMTs) are regulated by cadmium even as it is known that Lys biosynthesis and its degradation are modulated by novel mechanisms. Three complex pathways co-exist in plants for serine (Ser) biosynthesis, and the relative preponderance of each pathway in relation to plant development or abiotic stress tolerance are being unfolded slowly. But the phosphorylated pathway of L-Ser biosynthesis (PPSB) appears to play critical roles and is essential in plant metabolism and development. Ser, which participates indirectly in purine and pyrimidine biosynthesis and plays a pivotal role in plant metabolism and signaling. Also, L-Ser has been implicated in plant responses to both biotic and abiotic stresses. A large body of information implicates Lys-rich and serine/arginine-rich (SR) proteins in a very wide array of abiotic stresses. Interestingly, a link exists between Lys-rich K-segment and stress tolerance levels. It is of interest to note that abiotic stresses largely influence the expression patterns of SR proteins and also the alternative splicing (AS) patterns. We have checked if any lncRNAs form a cohort of differentially expressed genes from the publicly available PPSB, sequence read archives of NCBI GenBank. Finally, we discuss the link between Lys and Ser synthesis, catabolism, Lys-proteins, and SR proteins during plant development and their myriad roles in response to abiotic stresses.


2019 ◽  
Vol 51 (3) ◽  
pp. 229-242 ◽  
Author(s):  
Muhammad Khalid ◽  
Saeed-ur- Rahman ◽  
Danfeng Huang

Abstract The beneficial endophytic microorganisms have received significant attention in agriculture because of their exceptional capabilities to facilitate functions like nutrient enrichment, water status, and stress tolerance (biotic and abiotic). This review signifies the molecular mechanisms to better understand the Piriformospora indica-mediated plants improvement or protection for sustainable agriculture. P. indica, an endophytic fungus, belonging to the order Sebacinales (Basidiomycota), is versatile in building mutualistic associations with a variety of plants including pteridophytes, bryophytes, gymnosperms, and angiosperms. P. indica has enormous potential to manipulate the hormonal pathway such as the production of indole-3-acetic acid which in turn increases root proliferation and subsequently improves plant nutrient acquisition. P. indica also enhances components of the antioxidant system and expression of stress-related genes which induce plant stress tolerance under adverse environmental conditions. P. indica has tremendous potential for crop improvement because of its multi-dimensional functions such as plant growth promotion, immunomodulatory effect, biofertilizer, obviates biotic (pathogens) and abiotic (metal toxicity, water stress, soil structure, salt, and pH) stresses, phytoremediator, and bio-herbicide. Considering the above points, herein, we reviewed the physiological and molecular mechanisms underlying P. indica-mediated plants improvement or protection under diverse agricultural environment. The first part of the review focuses on the symbiotic association of P. indica with special reference to biotic and abiotic stress tolerance and host plant root colonization mechanisms, respectively. Emphasis is given to the expression level of essential genes involved in the processes that induce changes at the cellular level. The last half emphasizes critical aspects related to the seed germination, plant yield, and nutrients acquisition.


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