A N2-fixing endophyticBurkholderiasp. associated with maize plants cultivated in Mexico

2002 ◽  
Vol 48 (4) ◽  
pp. 285-294 ◽  
Author(s):  
Paulina Estrada ◽  
Patrick Mavingui ◽  
Benoit Cournoyer ◽  
Fanette Fontaine ◽  
Jacques Balandreau ◽  
...  

In the frame of a survey of potentially endophytic N2-fixing Burkholderia associated with maize in Mexico, its country of origin, the soil of an indigenous maize field near Oaxaca was studied. Under laboratory conditions, plant seedlings of two ancient maize varieties were used as a trap to select endophyte candidates from the soil sample. Among the N2fixers isolated from inside plant tissues and able to grow on PCAT medium, the most abundant isolates belonged to genus Burkholderia (API 20NE, rrs sequences). Representative isolates obtained from roots and shoots of different plants appeared identical (rrs and nifH RFLP), showing that they were closely related. In addition, their 16S rDNA sequences differed from described Burkholderia species and, phylogenetically, they constituted a separate deep-branching new lineage in genus Burkholderia. This indicated that these isolates probably constituted a new species. An inoculation experiment confirmed that these N2-fixing Burkholderia isolates could densely colonize the plant tissues of maize. More isolates of this group were subsequently obtained from field-grown maize and teosinte plants. It was hypothesized that strains of this species had developed a sort of primitive symbiosis with one of their host plants, teosinte, which persisted during the domestication of teosinte into maize.Key words: endophytic bacteria, nitrogen-fixation, Zea mays, Burkholderia.

2021 ◽  
Vol 38 ◽  
pp. 1-9
Author(s):  
Wei Wang ◽  
Yongzhong Cui ◽  
Xiaoming Chen ◽  
Nawaz Haider Bashir ◽  
Hang Chen

Plants and insects have co-existed for millions of years. Although research has been conducted on various insect species that induce galls on various plant tissues, information is particularly scarce when it comes to insects that form galls on the tough trunk of their host plants. This contribution describes the gall-inducing aphid Nipponaphis hubeiensis sp. nov. from the Zhushan County, Shiyan City, Hubei Province of China. This aphid induces enclosed galls with woody external layer on the trunk of Sycopsis sinensis (Saxifragales: Hamamelidaceae), an uncommon ecological niche in the aphid-plant interaction system. Morphological features for the identification of new species are provided. In addition, a partial sequence of the nuclear gene EF1α was amplified and sequenced to construct a cluster graph. Based on the clustering graph combined with morphology traits, the gall-forming aphid was classified into Nipponaphis. The unique ecological habits of this new aphid will bring innovative perspectives to the study of the evolution and diversity in aphid-host interaction.


2019 ◽  
pp. 28-39
Author(s):  
Tri Ratna Sulistiyani ◽  
Dinihari Indah Kusumawati

Endophytes are potential as a source of active compound producer. Endophytes that is isolated from tropical medicinal plants has been getting attention due to its high biodiversity and active compound producing ability. L-asparaginase is the first enzyme used as chemotherapeutic agent for leukemia. The aim of this study is to collect the endophytic bacteria associated with tropical medicinal plants from Sumba Island and investigate the activity of L-asparaginase without L-glutaminase from endophytic bacteria isolates. The samples Gliricidia sepium, Pittosporum moluccanum, Clerodendrum buchanani, and Zingiberaceae are collected from Wanggameti, East Sumba, NTT. Samples are sterilized using surface-sterilization method and endophytic bacteria are isolated using plant piece method on R2A media. Selected endophytic bacteria are identified by 16S rDNA sequences. L-asparaginase screening is conducted using modified R2A with addition of L-asparagine and phenol red as colour indicator. A total of 34 isolates of endophytic bacteria were collected from 5 samples. A total of 14 genus consisted of 17 different bacterial species were obtained from 34 selected isolates. Endophytic bacteria of P. stutzeri strains of SMKL1 and R. radiobacter strains of SMKW2 from the Kahili plant were needed as L-glutaminase-free L-asparaginase and were potential to be candidate of leukemia cancer chemotherapy


2020 ◽  
Vol 21 (5) ◽  
Author(s):  
Nita Shilfiani Rohmah Nita Shilfiani Rohmah ◽  
SUHARJONO ◽  
YOGA DWI JATMIKO ◽  
DIAN SISWANTO ◽  
IRFAN MUSTAFA

Abstract. Rohmah NS, Suharjono, Jatmiko YD, Siswanto D, Mustafa I. 2020. The potency of endophytic bacteria isolated from Ficus septica as phytoremediation promoting agent of Cr (VI) contaminated soil. Biodiversitas 21: 1920-1927. Endophytic bacteria tolerant of chromium have the potential to reduce Cr (VI) to Cr (III) and produce compounds that can improve plant survival in Cr (VI) contaminated soils. This study was performed to isolate and identify Cr (VI)-tolerant bacteria from the endosphere of Ficus septica Burm.F growing on the tannery waste contaminated soil, Screening of bacteria was carried out based on the level of Cr (VI) tolerance. High tolerant isolates were tested for their potential of Indole Acetic Acid (IAA) and exopolysaccharide (EPS) production, phosphate solubilizing, and the presence of chromate reductase (ChR) genes. The most potential bacterial isolate was identified based on 16S rDNA sequences. The results showed that three isolates (E3, E4, and E8) were tolerant of Cr (VI) up to 900 mg/L. E8 isolates produced the highest IAA production (20.05 μg/mL), phosphate solubilization (127.78 μg/mL), and EPS production (9,70 μg/mL), and all isolates had the ChR gene. E8 isolate was found to be 100% identical to Enterobacter cloacae ATCC 13047.


Crustaceana ◽  
2020 ◽  
Vol 93 (11-12) ◽  
pp. 1295-1313
Author(s):  
Si-Ying Mao ◽  
Chao Huang

Abstract A new genus new species of freshwater crab and a new Minpotamon Dai & Türkay, 1997 species are described from eastern Guangdong, China, based on morphology and mitochondrial 16S rDNA sequences. The new genus, Teoswamon gen. nov., is established for T. scolasticum sp. nov., which resembles species from several other genera from Guangdong, but its unique combination of carapace, male gonopod and female vulvae characters set it apart from others. Minpotamon kityang sp. nov. is almost identical with Minpotamon nasicum (Dai, Chen, Song, Fan, Lin & Zeng, 1979) externally, but differs drastically in the male gonopod morphology. Molecular analysis supports the current taxonomic treatments. Teoswamon scolasticum sp. nov. forms its own lineage closely related to Huananpotamon Dai & Ng, 1994. Minpotamon kityang sp. nov. clusters with Minpotamon nasicum, but their genetic distance is of an interspecific level.


1998 ◽  
Vol 88 (6) ◽  
pp. 550-555 ◽  
Author(s):  
T. K. Cotten ◽  
G. P. Munkvold

The roles of residue size and burial depth were assessed in the survival of Fusarium moniliforme, F. proliferatum, and F. subglutinans in maize stalk residue. Stalk pieces (small or large sizes) were soaked in a spore suspension of F. moniliforme, F. proliferatum, or F. subglutinans and placed in a field on the soil surface or buried at 15- or 30-cm depths. Residue pieces were recovered periodically, cultured on a selective medium, and microscopically examined for the presence of the inoculated Fusarium species. After 630 days, the inoculated Fusarium species were recovered from 0 to 50% of the inoculated stalk pieces in a long-term, continuous maize field, from 0 to 28% of the inoculated stalk pieces placed in a maize/soybean/oat rotation field, and from 0 to 25% of the noninoculated stalk pieces at both locations. Residue size and residue depth had significant effects on survival, but there were significant interactions among strain, depth, residue size, and time. Up to 343 days after placement in the field, survival of the three Fusarium species was not consistently different between buried residues and surface residues, but after 630 days, survival was greater from surface residues. Overall, fungus survival decreased more slowly in the surface residues than in the buried residues. Linear coefficients of determination ranged from 0.35 to 0.82 for the surface residues and from 0.81 to 0.98 for the buried residues. Decline in survival over time followed a more linear pattern in buried residues than in surface residues. Vegetative compatibility tests confirmed that F. moniliforme, F. proliferatum, and F. subglutinans strains can survive at least 630 days in surface or buried maize residue. These results demonstrate that maize residue can act as a long-term source of inoculum for infection of maize plants by these three Fusarium species.


1993 ◽  
Vol 114 (2) ◽  
pp. 173-177 ◽  
Author(s):  
A. Ibrahim ◽  
B.M. Goebel ◽  
W. Liesack ◽  
M. Griffiths ◽  
E. Stackebrandt

Zootaxa ◽  
2021 ◽  
Vol 5039 (3) ◽  
pp. 409-416
Author(s):  
AIHUAN ZHANG

Chinese species of the genus Gibberifera Obraztsov are reviewed. G. tetracornata sp. nov. is described as new to science with illustrations of adult and genitalia. Other species are summarized with detailed references cited and information about host-plants and distribution. A key to Chinese species of Gibberifera based on characters of male genitalia is given.  


2003 ◽  
Vol 52 (4) ◽  
pp. 365-369 ◽  
Author(s):  
K.E. Hill ◽  
C.E. Davies ◽  
M.J. Wilson ◽  
P. Stephens ◽  
K.G. Harding ◽  
...  

There is growing evidence to suggest that the resident microflora of chronic venous leg ulcers impairs cellular wound-healing responses, thereby playing an important role in maintaining the non-healing phenotype of many of these wounds. The significance of individual species of bacteria will remain unclear until it is possible to characterize fully the microflora of such lesions. The limitations and biases of culture-based microbiology are being realized and the subsequent application of molecular methods is revealing greater diversity within mixed bacterial populations than that demonstrated by culture alone. To date, this approach has been limited to a small number of systems, including the oral microflora. Here, for the first time, the comprehensive characterization of the microflora present in the tissue of a chronic venous leg ulcer is described by the comparison of 16S rDNA sequences amplified directly from the wound tissue with sequences obtained from bacteria that were isolated by culture. The molecular approach demonstrated significantly greater bacterial diversity than that revealed by culture. Furthermore, sequences were retrieved that may possibly represent novel species of bacteria. It is only by the comprehensive analysis of the wound microflora by both molecular and cultural methods that it will be possible to further our understanding of the role of bacteria in this important condition.


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