scholarly journals Yields and Disease Resistance of Fall-harvested Transgenic and Conventional Summer Squash in Kentucky

1999 ◽  
Vol 9 (2) ◽  
pp. 282-288 ◽  
Author(s):  
Brent Rowell ◽  
William Nesmith ◽  
John C. Snyder

Virus and fungal disease pressures limit fall production of summer squash (Cucurbita pepo L.) in Kentucky. Twenty-five summer squash cultivars (nine zucchini, eight yellow straightneck, and eight yellow crookneck entries) were evaluated for marketable yield, appearance, and disease resistance in a late summer planting. Genetically engineered virus-resistant materials and new conventionally bred resistant or tolerant cultivars were compared with popular susceptible hybrids. Virus incidence was determined visually before and after final harvest and was also determined by enzyme-linked immunosorbent assay (ELISA). Watermelon mosaic virus (WMV) was most frequently detected and appeared to have caused most of the observed symptoms. Conventionally bred cultivars containing the precocious yellow gene and two transgenic lines were in the highest yielding group of yellow straightneck squash despite high virus incidence in precocious yellow cultivars. Among yellow crooknecks, transgenic cultivars were clearly superior for disease resistance and yields. Conventionally bred cultivars with virus tolerance were among the highest yielding zucchini types. Most transgenics were superior to their nontransformed equivalent cultivars for virus resistance and yield. Cultivars and breeding lines varied considerably in color, shape, and overall appearance. ELISA results revealed that some (but not all) transgenic cultivars tested positive for the coat protein corresponding to the virus resistance present in that cultivar. Also, mild virus-like symptoms were observed in transgenic squash plants after the conclusion of harvest.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 534c-534
Author(s):  
Brent Rowell ◽  
William Nesmith ◽  
John C. Snyder

Kentucky vegetable growers exploiting a fall-harvested market window for summer squash (Cucurbita pepo L.) usually encounter severe virus and fungal disease pressure resulting in serious yield and quality reductions. Twenty-five summer squash varieties or advanced breeding lines (9 zucchini, 8 yellow straightneck, and 8 crookneck entries) were evaluated in a late summer planting for yield, quality, and disease resistance at the Univ. of Kentucky South Farm in Lexington. Both genetically engineered virus-resistant materials and new resistant/tolerant varieties from traditional breeding programs were compared with our recommended hybrids. Border rows of a virus-susceptible variety were planted alongside and between each of the four blocks to enhance virus spread throughout the trial. Virus incidence was determined visually before and after final harvest and leaf samples were collected for virus assays. Virus symptoms were absent or difficult to see on zucchini squash plants during most of the trial but became obvious near the final harvest date. Varieties from traditional breeding programs having virus tolerance were among the highest yielding zucchini types. Traditionally-bred cultivars with the precocious yellow gene and two transgenic lines were in the highest yielding group of yellow straightneck squash—in spite of high virus incidences in precocious yellow cultivars. Transgenic cultivars were clearly superior in terms of yields among yellow crooknecks with yields nearly double those of the lowest yielding traditional hybrids. Cultivars and breeding lines varied considerably in color, shape, overall appearance, and potential marketability.


1998 ◽  
Vol 8 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Jonathan R. Schultheis ◽  
S. Alan Walters

Yellow and zucchini squash (Cucurbita pepo L.) cultigens (breeding lines and cultivars) were evaluated over a 2-year (1995 and 1996) period in North Carolina. Yellow squash cultigens that performed well (based on total marketable yields) were `Destiny III', `Freedom III', `Multipik', XPHT 1815, and `Liberator III' in Fall 1995 and HMX 4716, `Superpik', PSX 391, `Monet', `Dixie', XPH 1780, and `Picasso' in Spring 1996. Some of the yellow squash cultigens evaluated had superior viral resistance: XPHT 1815, XPHT 1817, `Freedom III', `Destiny III', `Freedom II', TW 941121, `Prelude II', and `Liberator III' in Fall 1995 and XPHT 1815, `Liberator III', `Prelude II', and `Destiny III' in Fall 1996; all these cultigens were transgenic. The yellow squash cultigens that performed well (based on total marketable yields) in the Fall 1995 test had transgenic virus resistance (`Destiny III', `Freedom III', XPHT 1815, and `Liberator III') or had the Py gene present in its genetic background (`Multipik'). Based on total marketable yields, the best zucchini cultigens were XPHT 1800, `Tigress', XPHT 1814, `Dividend' (ZS 19), `Elite', and `Noblesse' in Fall 1995; and `Leonardo', `Tigress', `Hurricane', `Elite', and `Noblesse' in Spring 1996. The zucchini cultigens with virus resistance were TW 940966, XPHT 1814, and XPHT 1800 in Fall 1995 and XPHT 1800, XPHT 1776, XPHT 1777, XPHT 1814, and XPHT 1784 in Fall 1996. Even though TW 940966 had a high level of resistance in the Fall 1995 test, it was not as high yielding as some of the more susceptible lines. Viruses detected in the field were papaya ringspot virus (PRSV) and watermelon mosaic virus (WMV) for Fall 1995; while PRSV, zucchini yellow mosaic virus (ZYMV), and WMV were detected for Fall 1996. Summer squash cultigens transgenic for WMV and ZYMV have potential to improve yield, especially during the fall when viruses are more prevalent. Most transgenic cultigens do not possess resistance to PRSV, except XPHT 1815 and XPHT 1817. Papaya ringspot virus was present in the squash tests during the fall of both years. Thus, PRSV resistance must be transferred to the transgenic cultigens before summer squash can be grown during the fall season without the risk of yield loss due to viruses.


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Valliappan Karuppiah ◽  
Lu Zhixiang ◽  
Hongyi Liu ◽  
Murugappan Vallikkannu ◽  
Jie Chen

Abstract Background Retention of agricultural bio-mass residues without proper treatment could affect the subsequent plant growth. In the present investigation, the co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens has been employed for multiple benefits including the enrichment of lignocellulose biodegradation, plant growth, defense potential and disease resistance. Results The Vel1 gene predominantly regulates the secondary metabolites, sexual and asexual development as well as cellulases and polysaccharide hydrolases productions. Overexpression mutant of the Trichoderma asperellum Vel1 locus (TA OE-Vel1) enhanced the activity of FPAase, CMCase, PNPCase, PNPGase, xylanase I, and xylanase II through the regulation of transcription regulating factors and the activation of cellulase and xylanase encoding genes. Further, these genes were induced upon co-cultivation with Bacillus amyloliquefaciens (BA). The co-culture of TA OE-Vel1 + BA produced the best composition of enzymes and the highest biomass hydrolysis yield of 89.56 ± 0.61%. The co-culture of TA OE-Vel1 + BA increased the corn stover degradation by the secretion of cellulolytic enzymes and maintained the C/N ratio of the corn stover amended soil. Moreover, the TA OE-Vel1 + BA increased the maize plant growth, expression of defense gene and disease resistance against Fusarium verticillioides and Cohilohorus herostrophus. Conclusion The co-cultivation of genetically engineered T. asperellum and B. amyloliquefaciens could be utilized as a profound and meaningful technique for the retention of agro residues and subsequent plant growth.


Plant Disease ◽  
2004 ◽  
Vol 88 (2) ◽  
pp. 119-124 ◽  
Author(s):  
M. Grisoni ◽  
F. Davidson ◽  
C. Hyrondelle ◽  
K. Farreyrol ◽  
M. L. Caruana ◽  
...  

A survey was carried out to identify the viruses infecting vanilla in French Polynesia and to assess their incidence. Virus identification was based on enzyme-linked immunosorbent assay (ELISA) and, for potyviruses, on the sequence of part of the coat protein and inoculation assays. Between 1998 and 1999, 3,610 vanilla plants from 49 plots in the Society Islands were indexed. Cymbidium mosaic virus (CymMV) was detected in 500 vines from 10 plots in the Leeward Islands. The data suggest that this virus has spread widely since its first detection in French Polynesia in 1986, most likely through the dissemination of symptomless infected cuttings. Viruses belonging to the Potyvirus genus were found in 674 plants from 27 plots in the four islands surveyed. Three distinct potyviruses have been identified: (i) Vanilla mosaic virus, (ii) Watermelon mosaic virus, and (iii) and a virus related to Bean common mosaic virus. The symptoms induced on Vanilla tahitensis by the three potyviruses can be differentiated from each other and from those due to CymMV. A significant proportion of the plants surveyed (97/476) were symptomatic but tested negative by ELISA for CymMV and the Potyvirus group. Odontoglossum ringspot virus was not detected in any sample tested.


Plant Disease ◽  
2011 ◽  
Vol 95 (3) ◽  
pp. 263-268 ◽  
Author(s):  
S. K. Gremillion ◽  
A. K. Culbreath ◽  
D. W. Gorbet ◽  
B. G. Mullinix ◽  
R. N. Pittman ◽  
...  

Field experiments were conducted in 2002 to 2006 to characterize yield potential and disease resistance in the Bolivian landrace peanut (Arachis hypogaea) cv. Bayo Grande, and breeding lines developed from crosses of Bayo Grande and U.S. cv. Florida MDR-98. Diseases of interest included early leaf spot, caused by the fungus Cercospora arachidicola, and late leaf spot, caused by the fungus Cercosporidium personatum. Bayo Grande, MDR-98, and three breeding lines, along with U.S. cvs. C-99R and Georgia Green, were included in split-plot field experiments in six locations across the United States and Bolivia. Whole-plot treatments consisted of two tebuconazole applications and a nontreated control. Genotypes were the subplot treatments. Area under the disease progress curve (AUDPC) for percent defoliation due to leaf spot was lower for Bayo Grande and all breeding lines than for Georgia Green at all U.S. locations across years. AUDPC for disease incidence from one U.S. location indicated similar results. Severity of leaf spot epidemics and relative effects of the genotypes were less consistent in the Bolivian experiments. In Bolivia, there were no indications of greater levels of disease resistance in any of the breeding lines than in Bayo Grande. In the United States, yields of Bayo Grande and the breeding lines were greater than those of the other genotypes in 1 of 2 years. In Bolivia, low disease intensity resulted in the highest yields in Georgia Green, while high disease intensity resulted in comparable yields among the breeding lines, MDR-98, and C-99R. Leaf spot suppression by tebuconazole was greater in Bolivia than in the United States. This result indicates a possible higher level of fungicide resistance in the U.S. population of leaf spot pathogens. Overall, data from this study suggest that Bayo Grande and the breeding lines may be desirable germplasm for U.S. and Bolivian breeding programs or production.


1999 ◽  
Vol 354 (1383) ◽  
pp. 521-529 ◽  
Author(s):  
B. D. Harrison ◽  
T. M. A. Wilson

Beijerinck's (1898) recognition that the cause of tobacco mosaic disease was a novel kind of pathogen became the breakthrough which led eventually to the establishment of virology as a science. Research on this agent, tobacco mosaic virus (TMV), has continued to be at the forefront of virology for the past century. After an initial phase, in which numerous biological properties of TMV were discovered, its particles were the first shown to consist of RNA and protein, and X–ray diffraction analysis of their structure was the first of a helical nucleoprotein. In the molecular biological phase of research, TMV RNA was the first plant virus genome to be sequenced completely, its genes were found to be expressed by cotranslational particle disassembly and the use of subgenomic mRNA, and the mechanism of assembly of progeny particles from their separate parts was discovered. Molecular genetical and cell biological techniques were then used to clarify the roles and modes of action of the TMV non–structural proteins: the 126 kDa and 183 kDa replicase components and the 30 kDa cell–to–cell movement protein. Three different TMV genes were found to act as avirulence genes, eliciting hypersensitive responses controlled by specific, but different, plant genes. One of these (the N gene) was the first plant gene controlling virus resistance to be isolated and sequenced. In the biotechnological sphere, TMV has found several applications: as the first source of transgene sequences conferring virus resistance, in vaccines consisting of TMV particles genetically engineered to carry foreign epitopes, and in systems for expressing foreign genes. TMV owes much of its popularity as a research model to the great stability and high yield of its particles. Although modern methods have much decreased the need for such properties, and TMV may have a less dominant role in the future, it continues to occupy a prominent position in both fundamental and applied research.


Author(s):  
B. D. Harrison

SynopsisSome of the most successful early applications of genetic engineering in crop improvement have been in the production of virus-resistant plants. This has been achieved not by the transfer of naturally occurring resistance genes from one plant species or variety to another but by transformation with novel resistance genes based on nucleotide sequences derived from the viruses themselves or from virus-associated nucleic acids. Transformation of plants with a DNA copy of the particle protein gene of viruses that have positive-sense single-stranded RNA genomes typically confers resistance to infection with the homologous and closely related viruses. Transformation with a gene that is transcribed to produce a benign viral satellite RNA can confer virus-specific tolerance of infection. In addition, recent work with viral poly-merase gene-related sequences offers much promise, and research is active on other strategies such as the use of virus-specific ribozymes.Already the field trialling of plants incorporating transgenic virus resistance has begun, with encouraging results, and effects on virus spread are being studied. Deployment strategies for the resistant plants must now be devised and the conjectural hazards of growing them assessed. Genetically engineered virus resistance promises to make a major contribution to the control of plant virus diseases by non-chemical methods.


1995 ◽  
Vol 25 (8) ◽  
pp. 1340-1345 ◽  
Author(s):  
John D. Castello ◽  
George D. Bachand ◽  
Philip M. Wargo ◽  
Volker Jacobi ◽  
Donald R. Tobi ◽  
...  

Tomato mosaic tobamovirus (ToMV) was detected by enzyme-linked immunosorbent assay in the roots of red spruce (Picearubens Sarg.) on Whiteface Mountain, New York. Both virus incidence and concentration in the roots of red spruce vary by site and were greater in trees with little to moderate crown dieback than in trees with severe dieback. There was no significant association between virus incidence or concentration in the roots of red spruce and elevation on Whiteface Mountain. Multiple regression analysis of virus concentration in the roots, as the dependent variable, was performed against nine selected crown and root variables. In the final regression model, the number of live second-order nonwoody roots per length of first-order nonwoody root and length of the live crown were positively and negatively correlated, respectively, with virus concentration in the roots. These results suggest a complex epidemiology and a potentially significant impact of ToMV infection on the growth of red spruce on Whiteface Mountain.


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