scholarly journals Classical Soybean (Glycine max (L.) Merr) Symbionts, Sinorhizobium fredii USDA191 and Bradyrhizobium diazoefficiens USDA110, Reveal Contrasting Symbiotic Phenotype on Pigeon Pea (Cajanus cajan (L.) Millsp)

2019 ◽  
Vol 20 (5) ◽  
pp. 1091 ◽  
Author(s):  
Alaa Alaswad ◽  
Nathan Oehrle ◽  
Hari Krishnan

Pigeon pea (Cajanus cajan (L.) Millspaugh) is cultivated widely in semiarid agricultural regions in over 90 countries around the world. This important legume can enter into symbiotic associations with a wide range of rhizobia including Bradyrhizobium and fast-growing rhizobia. In comparison with other major legumes such as soybean and common bean, only limited information is available on the symbiotic interaction of pigeon pea with rhizobia. In this study, we investigated the ability of two classical soybean symbionts—S. fredii USDA191 and B. diazoefficiens USDA110—and their type 3 secretion system (T3SS) mutants, to nodulate pigeon pea. Both S. fredii USDA191 and a T3SS mutant S. fredii RCB26 formed nitrogen-fixing nodules on pigeon pea. Inoculation of pigeon pea roots with B. diazoefficiens USDA110 and B. diazoefficiens Δ136 (a T3SS mutant) resulted in the formation of Fix− and Fix+ nodules, respectively. Light and transmission electron microscopy of Fix- nodules initiated by B. diazoefficiens USDA110 revealed the complete absence of rhizobia within these nodules. In contrast, Fix+ nodules formed by B. diazoefficiens Δ136 revealed a central region that was completely filled with rhizobia. Ultrastructural investigation revealed the presence of numerous bacteroids surrounded by peribacteroid membranes in the infected cells. Analysis of nodule proteins by one- and two-dimensional gel electrophoresis revealed that leghemoglobin was absent in B. diazoefficiens USDA110 nodules, while it was abundantly present in B. diazoefficiens Δ136 nodules. Results of competitive nodulation assays indicated that B. diazoefficiens Δ136 had greater competitiveness for nodulation on pigeon pea than did the wild type strain. Our results suggest that this T3SS mutant of B. diazoefficiens, due to its greater competitiveness and ability to form Fix+ nodules, could be exploited as a potential inoculant to boost pigeon pea productivity.

Author(s):  

Abstract A new distribution map is provided for Planococcus kenyae (Le Pelley) Hemiptera: Coccoidea: Pseudococcidae Attacks a wide range of tropical and subtropical crops including coffee (Coffea spp.), pigeon pea (Cajanus cajan), yam (Dioscorea spp.), sugarcane (Saccharum officinarum), sweet potato (Ipomoea batatas), Citrus and cocoa (Theobroma cacao). Information is given on the geographical distribution in AFRICA, Congo, Congo Democratic Republic, Cote d'Ivoire, Ghana, Kenya, Malawi, Nigeria, Sierra Leone, Sudan, Tanzania, Togo, Uganda, Zimbabwe.


1972 ◽  
Vol 14 (3) ◽  
pp. 545-548
Author(s):  
D. Sharma ◽  
Laxman Singh ◽  
S. S. Baghel ◽  
H. K. Sharma

Diallel analysis for seed size on 10 varieties of pigeon pea or arhar Cajanus cajan L. Millsp., representing different maturity groups and wide range of variability in seed size, was conducted to determine genetic parameters. The D and H1 components indicated a predominance of additive gene effects and the degree of dominance was in the partial dominance range. Seed size was simply inherited with a high heritability value of 0.82. The scatter of parental arrays in a Wr, Vr graph suggested that the genes controlling smaller seed size were dominant over the genes controlling larger seed size. The analysis indicated the possibility of improving seed size by simple selection procedures.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ana Mafalda Dordio ◽  
Relja Beck ◽  
Telmo Nunes ◽  
Isabel Pereira da Fonseca ◽  
Jacinto Gomes

Abstract Background Canine vector-borne diseases (CVBDs) are caused by a wide range of pathogens transmitted by arthropods. They have been an issue of growing importance in recent years; however, there is limited information about the vector-borne pathogens circulating in Portugal. The aim of the present study was to detect canine vector-borne bacteria and protozoa of veterinary and zoonotic importance using molecular methods. Methods One hundred and forty-two dogs from Lisbon, southern Portugal, were tested: 48 dogs from a veterinary hospital clinically suspected of vector-borne diseases and 94 apparently healthy dogs from shelters. Anaplasma spp./Ehrlichia spp., Babesia/Theileria spp., Hepatozoon spp., and Mycoplasma spp. infections were detected by PCR from blood samples and examined under light microscopy. Other information including clinical status and diagnostic test results were collected for each animal. Results Infections were detected by PCR in 48 (33.80%) dogs. Single infections were found in 35 dogs (24.64%), and co-infections were found in 13 (9.15%) dogs. Twenty-nine (20.42%) dogs were positive for Hepatozoon spp., 15 (10.56%) for Mycoplasma spp., 11 (7.75%) for Anaplasma spp./Ehrlichia spp., and six (4.21%) for Babesia spp. DNA sequencing was used to identify Babesia vogeli (2.81%), Babesia canis (1.40%), Hepatozoon canis (20.42%), Mycoplasma haematoparvum (2.11%), Mycoplasma haemocanis (8.45%), Anaplasma platys (7.04%), and Ehrlichia canis (0.70%). Conclusions This is the first molecular identification of B. canis and M. haematoparvum in dogs from southern Portugal. This study highlights the importance of molecular methods to identify CVBD pathogens in endemic areas and helps to guide the clinical approach of veterinarians in practice.


Author(s):  
Yan Chen ◽  
Ward Whitt

In order to understand queueing performance given only partial information about the model, we propose determining intervals of likely values of performance measures given that limited information. We illustrate this approach for the mean steady-state waiting time in the $GI/GI/K$ queue. We start by specifying the first two moments of the interarrival-time and service-time distributions, and then consider additional information about these underlying distributions, in particular, a third moment and a Laplace transform value. As a theoretical basis, we apply extremal models yielding tight upper and lower bounds on the asymptotic decay rate of the steady-state waiting-time tail probability. We illustrate by constructing the theoretically justified intervals of values for the decay rate and the associated heuristically determined interval of values for the mean waiting times. Without extra information, the extremal models involve two-point distributions, which yield a wide range for the mean. Adding constraints on the third moment and a transform value produces three-point extremal distributions, which significantly reduce the range, producing practical levels of accuracy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaochen Zhao ◽  
Victor H. Rivera-Monroy ◽  
Luis M. Farfán ◽  
Henry Briceño ◽  
Edward Castañeda-Moya ◽  
...  

AbstractMangroves are the most blue-carbon rich coastal wetlands contributing to the reduction of atmospheric CO2 through photosynthesis (sequestration) and high soil organic carbon (C) storage. Globally, mangroves are increasingly impacted by human and natural disturbances under climate warming, including pervasive pulsing tropical cyclones. However, there is limited information assessing cyclone’s functional role in regulating wetlands carbon cycling from annual to decadal scales. Here we show how cyclones with a wide range of integrated kinetic energy (IKE) impact C fluxes in the Everglades, a neotropical region with high cyclone landing frequency. Using long-term mangrove Net Primary Productivity (Litterfall, NPPL) data (2001–2018), we estimated cyclone-induced litterfall particulate organic C (litter-POC) export from mangroves to estuarine waters. Our analysis revealed that this lateral litter-POC flux (71–205 g C m−2 year−1)—currently unaccounted in global C budgets—is similar to C burial rates (69–157 g C m−2 year−1) and dissolved inorganic carbon (DIC, 61–229 g C m−2 year−1) export. We proposed a statistical model (PULITER) between IKE-based pulse index and NPPL to determine cyclone’s impact on mangrove role as C sink or source. Including the cyclone’s functional role in regulating mangrove C fluxes is critical to developing local and regional climate change mitigation plans.


2016 ◽  
Vol 29 (11) ◽  
pp. 862-877 ◽  
Author(s):  
Hari B. Krishnan ◽  
Alaa A. Alaswad ◽  
Nathan W. Oehrle ◽  
Jason D. Gillman

Legumes form symbiotic associations with soil-dwelling bacteria collectively called rhizobia. This association results in the formation of nodules, unique plant-derived organs, within which the rhizobia are housed. Rhizobia-encoded nitrogenase facilitates the conversion of atmospheric nitrogen into ammonia, which is utilized by the plants for its growth and development. Fatty acids have been shown to play an important role in root nodule symbiosis. In this study, we have investigated the role of stearoyl-acyl carrier protein desaturase isoform C (SACPD-C), a soybean enzyme that catalyzes the conversion of stearic acid into oleic acid, which is expressed in developing seeds and in nitrogen-fixing nodules. In-depth cytological investigation of nodule development in sacpd-c mutant lines M25 and MM106 revealed gross anatomical alteration in the sacpd-c mutants. Transmission electron microscopy observations revealed ultrastructural alterations in the sacpd-c mutants that are typically associated with plant defense response to pathogens. In nodules of two sacpd-c mutants, the combined jasmonic acid (JA) species (JA and the isoleucine conjugate of JA) were found to be reduced and 12-oxophytodienoic acid (OPDA) levels were significantly higher relative to wild-type lines. Salicylic acid levels were not significantly different between genotypes, which is divergent from previous studies of sacpd mutant studies on vegetative tissues. Soybean nodule phytohormone profiles were very divergent from those of roots, and root profiles were found to be almost identical between mutant and wild-type genotypes. The activities of antioxidant enzymes, ascorbate peroxidase, and superoxide dismutase were also found to be higher in nodules of sacpd-c mutants. PR-1 gene expression was extremely elevated in M25 and MM106, while the expression of nitrogenase was significantly reduced in these sacpd-c mutants, compared with the parent ‘Bay’. Two-dimensional gel electrophoresis and matrix-assisted laser desorption-ionization time of flight mass spectrometry analyses confirmed sacpd-c mutants also accumulated higher amounts of pathogenesis-related proteins in the nodules. Our study establishes a major role for SACPD-C activity as essential for proper maintenance of soybean nodule morphology and physiology and indicates that OPDA signaling is likely to be involved in attenuation of nodule biotic defense responses.


2014 ◽  
Vol 28 (2) ◽  
pp. 198-205 ◽  
Author(s):  
Prakash G Pati ◽  
Subhojit Datta ◽  
Ikechukwu O Agbagwa ◽  
Indra Prakash Singh ◽  
Khela Ram Soren ◽  
...  

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