Differential selection pressure exerted by root rot disease on the microbial communities in the rhizosphere of avocado ( Persea americana Mill.)

2019 ◽  
Vol 175 (3) ◽  
pp. 376-387 ◽  
Author(s):  
Bo Shu ◽  
Liqin Liu ◽  
Yongzan Wei ◽  
Dejian Zhang ◽  
Shengyou Shi
2021 ◽  
Author(s):  
Pan Pan Wang ◽  
Li Fang Yang ◽  
Jia Ling Sun ◽  
Ye Yang ◽  
Yuan Qu ◽  
...  

Abstract Background: Panax notoginseng (Burkill) F. H. Chen is a Chinese medicinal plant of the Araliaceae family commonly used in the treatment of cardiovascular and cerebrovascular diseases in Asia and elsewhere. To meet an increase in Chinese herbal medicine market demand, most P. notoginseng is planted artificially, and is vulnerable to various plant diseases. Root rot disease, in particular, causes substantial P. notoginseng yield reduction and economic losses. High-depth next-generation sequencing technology was used to analyze the rhizosphere and root endophyte microbial communities of P. notoginseng to compare the characteristics of these two communities between healthy and root rot diseased P. notoginseng plants, and to clarify the relationship between these microbial communities and root rot disease.Results: The P. notoginseng rhizosphere microbial community was more diverse than the root endophyte community, and the difference in functional pathways between healthy and diseased P. notoginseng plants was greater in the root endophyte than in the rhizosphere communities. Multi-database annotation results showed that the highest number of endophytic bacteria occurred in the roots of diseased plants. The number of carbohydrate-active enzymes database families was also higher in diseased roots. The RND antibiotic efflux function was higher in the healthy samples. A high abundance of Variovorax paradoxus and Pseudomonas fluorescens occurred in the healthy and diseased root endophyte communities, respectively. Ilyonectria mors-panacis and Pseudopyrenochaeta lycopersici were most abundant in the diseased samples. In addition, the complete genome of two unknown Flavobacteriaceae species and one unknown Bacteroides species were obtained based on binning analysis.Conclusions: The rhizosphere and root endophyte microbial communities of healthy and root rot diseased P. notoginseng showed marked differences in diversity and functional pathways. The higher mapping values obtained for the diseased samples reflected the occurrence of root rot disease at the molecular level. Variovorax paradoxus and Pseudomonas fluorescens may be antagonistic bacteria of root rot in P. notoginseng, whereas Ilyonectria mors-panacis and Pseudopyrenochaeta lycopersici appear to be P. notoginseng root rot pathogens. Our study provides a theoretical basis for understanding the occurrence of root rot in P. notoginseng and for further research on potential biological control agents.


2022 ◽  
Vol 12 ◽  
Author(s):  
Panpan Wang ◽  
Lifang Yang ◽  
Jialing Sun ◽  
Ye Yang ◽  
Yuan Qu ◽  
...  

Panax notoginseng (Burk.) F. H. Chen is a Chinese medicinal plant of the Araliaceae family used for the treatment of cardiovascular and cerebrovascular diseases in Asia. P. notoginseng is vulnerable to root rot disease, which reduces the yield of P. notoginseng. In this study, we analyzed the rhizosphere soil and root endophyte microbial communities of P. notoginseng from different geographical locations using high-throughput sequencing. Our results revealed that the P. notoginseng rhizosphere soil microbial community was more diverse than the root endophyte community. Rhodopseudomonas, Actinoplanes, Burkholderia, and Variovorax paradoxus can help P. notoginseng resist the invasion of root rot disease. Ilyonectria mors-panacis, Pseudomonas fluorescens, and Pseudopyrenochaeta lycopersici are pathogenic bacteria of P. notoginseng. The upregulation of amino acid transport and metabolism in the soil would help to resist pathogens and improve the resistance of P. notoginseng. The ABC transporter and gene modulating resistance genes can improve the disease resistance of P. notoginseng, and the increase in the number of GTs (glycosyltransferases) and GHs (glycoside hydrolases) families may be a molecular manifestation of P. notoginseng root rot. In addition, the complete genomes of two Flavobacteriaceae species and one Bacteroides species were obtained. This study demonstrated the microbial and functional diversity in the rhizosphere and root microbial community of P. notoginseng and provided useful information for a better understanding of the microbial community in P. notoginseng root rot. Our results provide insights into the molecular mechanism underlying P. notoginseng root rot and other plant rhizosphere microbial communities.


2019 ◽  
Vol 432 ◽  
pp. 932-941 ◽  
Author(s):  
Yuxing Feng ◽  
Yuanyuan Hu ◽  
Jiasheng Wu ◽  
Junhui Chen ◽  
Kim Yrjälä ◽  
...  

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Hammad Abdelwanees Ketta ◽  
Omar Abd El-Raouf Hewedy

Abstract Background Root rot pathogens reported to cause considerable losses in both the quality and productivity of common bean (Phaseolus vulgaris L.) and pea (Pisum sativum L.). It is an aggressive crop disease with detriment economic influence caused by Fusarium solani and Rhizoctonia solani among other soil-borne fungal pathogens. Destructive plant diseases such as root rot have been managed in the last decades using synthetic pesticides. Main body Seeking of economical and eco-friendly alternatives to combat aggressive soil-borne fungal pathogens that cause significant yield losses is urgently needed. Trichoderma emerged as promising antagonist that inhibits pathogens including those inducing root rot disease. Detailed studies for managing common bean and pea root rot disease using different Trichoderma species (T. harzianum, T. hamatum, T. viride, T. koningii, T. asperellum, T. atroviridae, T. lignorum, T. virens, T. longibrachiatum, T. cerinum, and T. album) were reported both in vitro and in vivo with promotion of plant growth and induction of systemic defense. The wide scale application of selected metabolites produced by Trichoderma spp. to induce host resistance and/or to promote crop yield, may represent a powerful tool for the implementation of integrated pest management strategies. Conclusions Biological management of common bean and pea root rot-inducing pathogens using various species of the Trichoderma fungus might have taken place during the recent years. Trichoderma species and their secondary metabolites are useful in the development of protection against root rot to bestow high-yielding common bean and pea crops.


2021 ◽  
Vol 7 (3) ◽  
pp. 195
Author(s):  
Amr H. Hashem ◽  
Amer M. Abdelaziz ◽  
Ahmed A. Askar ◽  
Hossam M. Fouda ◽  
Ahmed M. A. Khalil ◽  
...  

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Farid Abd-El-Kareem ◽  
Ibrahim E. Elshahawy ◽  
Mahfouz M. M. Abd-Elgawad

Abstract Background Black root rot of strawberry plants caused by Rhizoctonia solani, Fusarium solani, and Pythium sp. is a serious disease in Egypt. Biocontrol agents have frequently proved to possess paramount and safe tools against many diseases. The impact of soil treatments with 3 Bacillus pumilus isolates on black root rot disease of strawberry plants caused by R. solani, F., and Pythium sp. under laboratory and field conditions was examined herein on the commonly used ‘Festival’ strawberry cultivar. To increase the bacterial adhesion and distribution on the roots, each seedling was dipped in bacterial cell suspension at 1 × 108 colony-forming units/ml of each separate bacterial isolate for 30 min then mixed with 5% Arabic gum. Results The tested B. pumilus isolates significantly reduced the growth area of these 3 fungi. The two bacterial isolates Nos. 2 and 3 reduced the growth area by more than 85.2, 83.6, and 89.0% for R. solani, F. solani, and Pythium sp., respectively. Likewise, the 3 bacterial isolates significantly (P ≤ 0.05) inhibited the disease under field conditions. Isolates Nos. 2 and 3 suppressed the disease incidence by 64.4 and 68.9% and disease severity by 65.3 and 67.3%, respectively. The fungicide Actamyl had effect similar to that of the 2 isolates. B. pumilus isolates significantly enhanced growth parameters and yields of strawberry plants; isolates Nos. 2 and 3 raised the yield by 66.7 and 73.3%, respectively. Conclusions Bacillus pumilus isolates could effectively manage the black rot disease in strawberry herein. Due to the significant impact of the root rot disease on strawberry yield, B. pumilus should be further tested to manage the disease on strawberry on large scale in Egypt.


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