Tetragonia expansa Murr.

Keyword(s):  
2014 ◽  
Vol 77 (10) ◽  
pp. 1768-1772 ◽  
Author(s):  
ANA CAROLINA B. REZENDE ◽  
MARIA CRYSTINA IGARASHI ◽  
MARIA TERESA DESTRO ◽  
BERNADETTE D. G. M. FRANCO ◽  
MARIZA LANDGRAF

This study evaluated the effects of irradiation on the reduction of Shiga toxin–producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10-values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.


2003 ◽  
Vol 93 (11) ◽  
pp. 1445-1451 ◽  
Author(s):  
Takashi Kobori ◽  
Takeshi Osaki ◽  
Satoshi T. Ohki

A potential regulatory site for Cucumber mosaic virus (CMV, pepo strain) movement necessary to establish systemic infection was identified through immunological and hybridization studies on Tetragonia expansa, which was systemically infected by CMV at 36°C but not at 24°C. In inoculated leaves, cell-to-cell movement of CMV was enhanced at 36°C compared with that observed at 24°C. CMV was distributed in the phloem cells of minor veins as well as epidermal and mesophyll cells at both 36 and 24°C. CMV was detected in the petioles of inoculated leaves, stems, and petioles of uninoculated upper leaves at 36°C, whereas CMV was detected only in the petioles of inoculated leaves and in stems at 24°C. CMV moved into the phloem and was transported to the stem within 24 h postinoculation (hpi) at 36°C. However, it did not accumulate in the petioles of the upper leaves until 36 hpi. In petioles of inoculated leaves at 24°C, CMV was detected in the external phloem but not in the internal phloem. From these results, we conclude that systemic infection is established after viral entrance into the phloem pathway in T. expansa at 36°C.


Plant Disease ◽  
2010 ◽  
Vol 94 (4) ◽  
pp. 471-476 ◽  
Author(s):  
Cord Mikona ◽  
Wilhelm Jelkmann

Grapevine leafroll-associated virus-7 (GLRaV-7) was transmitted from an Albanian grapevine accession to Tetragonia expansa by the parasitic dodder Cuscuta reflexa and to Nicotiana occidentalis by Cuscuta europea. Cuscuta campestris was infected by GLRaV-7 but could not transfer the virus to an experimental host. Transmission of the virus was verified by reverse transcription–polymerase chain reaction (RT-PCR) from total nucleic acid (TNA) and double-stranded RNA (dsRNA) extracts from all five plant species. DsRNA extractions separated on agarose gels showed strong visible bands corresponding to high-molecular-weight virus genome and to subgenomic RNA. GLRaV-7 was maintained in C. reflexa, C. campestris, T. expansa, and N. occidentalis for more than 4 years. Infected T. expansa and the Cuscuta species remained symptomless while N. occidentalis showed severe symptoms leading to stunting and decline of the plants. Quantitative PCR showed great differences in the titer of GLRaV-7 between the tissues of its natural and experimental host plants. This is the first report on a virus of the Closteroviridae that was successfully transmitted to an herbaceous plant by dodder. Virus replication could be demonstrated in Cuscuta. Both the new experimental hosts of GLRaV-7 and Cuscuta allowed extraction of dsRNA for further characterization of the viral genome, which previously required grapevine scraping of phloem. This is time-consuming and does not always lead to satisfactory results. These alternative hosts of GLRaV-7 facilitate nucleic acid extractions and could be used as model plants for etiological studies.


1975 ◽  
Vol 32 (0) ◽  
pp. 233-252
Author(s):  
M.C. Thomaz ◽  
H.P. Haag ◽  
G.D. De Oliveira ◽  
J.R. Sarruge
Keyword(s):  

O presente trabalho teve como finalidade, estudar alguns aspectos da nutrição mineral do espinafre (Tetragonia expansa Murr.) no que concerne à composição química e a avaliação das quantidades de nutrientes extraídos e exportados pela cultura, nas diversas etapas de seu desenvolvimento. Para isto foi instalado um experimento de campo usando as práticas culturais normais. Amostragens periódicas foram feitas de acordo com o desenvolvimento das plantas. Conclui-se que: - a máxima produção de matéria seca das tolhas ocorre nos 93 dias e a época de maior exigência corresponde aos 63 dias; - a época de extração máxima dos nutrientes pelas folhas está entre 93 a 106 dias; - as quantidades extraídas pela parte aérea aos 90 dias, por ha, são: N- 39,7 kg; P- 4,7 kg; K- 120,6 kg; Ca- 24,8 kg; Mg- 16,0 kg; S-5,7 kg; B- 149,4 g; Cu- 34,4 g; Fe- 592,8 g; Mn- 462,2 g; Zn- 147,9 g; Mo- 2,2 g.


2007 ◽  
Vol 97 (10) ◽  
pp. 1245-1254 ◽  
Author(s):  
John J. Weiland ◽  
David Van Winkle ◽  
Michael C. Edwards ◽  
Rebecca L. Larson ◽  
Weilin L. Shelver ◽  
...  

The first reported U.S. isolate of Beet black scorch necrovirus (BBSV) was obtained and characterized. Host range of the virus for localized and occasionally systemic infection included the Chenopodiaceae and Tetragonia expansa; Nicotiana benthamiana supported symptomless systemic infection by the virus. The complete nucleotide sequence of the genomic RNA of the virus, designated BBSV-Co, exhibits 93% similarity to the genome of the ‘Ningxia’ isolate of BBSV from China. Amino acid sequence similarity in predicted genes ranged from 95% in the p4 gene to 97% in the p82 and coat protein genes. A potential additional gene exists within the U.S. isolate of BBSV that is absent from Chinese isolates of BBSV due to nucleotide differences between these isolates within the coat protein gene. Coat protein analysis by isoelectric focusing and by mass spectroscopy indicated the presence of phosphorylated residues. Using primer extension analysis of the 5′ end of the genome and site-directed mutants of genomic clones of BBSV-Co from which infectious RNA was produced, the native 5′ end of the BBSV-Co genome was determined to be 5′-GAAACCTAACC…3′, lacking the two terminal adenosine nucleotides in the published sequences of BBSV from China.


1979 ◽  
Vol 18 (10) ◽  
pp. 1765-1766 ◽  
Author(s):  
M.S. Kemp ◽  
R.S. Burden ◽  
C. Brown

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