scholarly journals Expression of “Rooting” Genes iaaM and rolB Under Regulatory Promoters in Tobacco

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 481E-482
Author(s):  
Wayne A. Sargent ◽  
Zong-Ming Cheng

Hybrid aspen is a major source of fiber in the north-central United States. One major problem for utilizing genetically improved aspen, and a variety of other woody species, is the difficulty in rooting hardwood cuttings. The objective of this project was to construct and confirm the function of genetic transformation vectors with two rooting genes (iaaM from Agrobacterium tumefaciens and rolB from A. rhizogenes) using three promoters (CaMV35S, soybean heat shock-inducible and poplar wound-inducible promoters). The gene constructs can be used to transform aspen for improvement of rooting hardwood cuttings and to elucidate rooting mechanisms. Each of these six gene constructs was inserted contiguously upstream from the promoter-less-glucuronidase (GUS) gene in the plasmid pBI 101. The engineered plasmids were transformed into A. tumefaciens strain LBA 4404 by electroporation. The functions of the genes were confirmed by transforming Nicotiana tabacum with these constructs. In plants transformed with iaaM and rolB under the CaMV35S promoter, the GUS gene expressed constitutively. These plants were also morphologically abnormal, with callus (and sometimes root) formation on stem tissue. The plants transformed with heat shock and Win6 constructs had no root formation and little or no GUS expression, without induction. After induction with heat shock (42°C for 1 hr per day for 7 days) or wounding (wounding the plants daily for 7 days), root formation occurred and GUS expression increased significantly with each gene, respectively. No roots developed in the non-transformed control shoots. The transformed plants with the regulatory promoters appeared morphologically normal. These constructs are currently being tested in hybrid aspen.

PLoS ONE ◽  
2015 ◽  
Vol 10 (9) ◽  
pp. e0139188 ◽  
Author(s):  
Laura Aldrich-Wolfe ◽  
Steven Travers ◽  
Berlin D. Nelson

Koedoe ◽  
1995 ◽  
Vol 38 (2) ◽  
Author(s):  
A.J. Viljoen

All observations and data related to the impact of the 1991/92 drought on the woody vegetation, excluding the riverine vegetation of major rivers, are summarised. This includes data from a visual estimate of damage from aerial photographs, surveys on selected sites, and general observations. Despite lower rainfall, the area north of the Olifants River (excluding the far-northern part) was less affected than the area south of it, suggesting that the woody vegetation in the north is more adapted to drought. A characteristic of the drought was the localised distribution pattern and variable intensity of damage to the same species in the same general area. Information on 31 species are presented briefly. Although a large number of woody species was to some extent damaged, when the woody vegetation is considered as a whole, the influence of the drought was not very severe.


2000 ◽  
Vol 90 (9) ◽  
pp. 1039-1042 ◽  
Author(s):  
G. M. Tabor ◽  
T. L. Kubisiak ◽  
N. B. Klopfenstein ◽  
R. B. Hall ◽  
H. S. McNabb McNabb

In the north central United States, leaf rust caused by Melampsora medusae is a major disease problem on Populus deltoides. In this study we identified molecular markers linked to a M. medusae resistance locus (Lrd1) that was segregating 1:1 within an intraspecific P. deltoides family (C9425DD). Previous field results were confirmed in the controlled environment of a growth chamber through an excised whole-leaf inoculation method. Using bulked segregant analysis we identified two random amplified polymorphic DNA (RAPD) markers (OPG10340 and OPZ191800) that are linked to Lrd1. Based on segregation in a total of 116 progeny, the genetic distances between OPG10340 and OPZ191800 and the resistance locus were estimated as 2.6 and 7.4 Haldane centimorgans (cM), respectively. Multipoint linkage analyses strongly suggest the most likely order for these loci is Lrd1, OPG10340, and OPZ191800. These markers may prove to be instrumental in the eventual cloning of Lrd1, as well as for marker-assisted selection of leaf-rust resistant genotypes.


1995 ◽  
Vol 52 (2) ◽  
pp. 416-424 ◽  
Author(s):  
James W. LaBaugh

Algal chlorophyll a is commonly used as a surrogate for algal biomass. Data from three lakes in western Nebraska, five wetlands in north-central North Dakota, and two lakes in north-central Minnesota represented a range in algal biovolume of over four orders of magnitude and a range in chlorophyll a from less than 1 to 380 mg∙m−3. Analysis of these data revealed that there was a linear relation, log10 algal biovolume = 5.99 + 0.09 chlorophyll a (r2 = 0.72), for cases in which median values of chlorophyll a for open-water periods were less than 20 mg∙m−3. There was no linear relation in cases in which median chlorophyll a concentrations were larger than 20 mg∙m−3 for open-water periods, an occurrence found only in shallow prairies lakes and wetlands for years in which light penetration was the least.


1987 ◽  
Vol 1 (4) ◽  
pp. 341-349 ◽  
Author(s):  
R. Gordon Harvey ◽  
J. H. Dekker ◽  
Richard S. Fawcett ◽  
Fred W. Roeth ◽  
Robert G. Wilson

Research conducted since 1979 in the north central United States and southern Canada demonstrated that after repeated annual applications of the same thiocarbamate herbicide to the same field, control of some difficult-to-control weed species was reduced. Laboratory studies of herbicide degradation in soils from these fields indicated that these performance failures were due to more rapid or “enhanced” biodegradation of the thiocarbamate herbicides after repeated use with a shorter period during which effective herbicide levels remained in the soils. Weeds such as wild proso millet [Panicum miliaceumL. spp.ruderale(Kitagawa) Tzevelev. #3PANMI] and shattercane [Sorghum bicolor(L.) Moench. # SORVU] which germinate over long time periods were most likely to escape these herbicides after repeated use. Adding dietholate (O,O-diethylO-phenyl phosphorothioate) to EPTC (S-ethyl dipropyl carbamothioate) reduced problems caused by enhanced EPTC biodegradation in soils treated previously with EPTC alone but not in soils previously treated with EPTC plus dietholate. While previous use of other thiocarbamate herbicides frequently enhanced biodegradation of EPTC or butylate [S-ethyl bis(2-methylpropyl)carbamothioate], previous use of other classes of herbicides or the insecticide carbofuran (2,3 -dihydro-2,2 -dimethyl-7-benzofuranyl methylcarbamate) did not. Enhanced biodegradation of herbicides other than the thiocarbamates was not observed.


2015 ◽  
Vol 107 (4) ◽  
pp. 1401-1410 ◽  
Author(s):  
Yi Wang ◽  
Matthew D. Ruark ◽  
Amanda J. Gevens ◽  
Don T. Caine ◽  
Amanda L. Raster ◽  
...  

2020 ◽  
Vol 14 (2) ◽  
pp. 413-433
Author(s):  
William J. McFarland, ◽  
Danielle Cotton, ◽  
Mac H. Alford ◽  
Micheal A. Davis

Longleaf pine (Pinus palustris Mill.) ecosystems exhibit high species diversity and are major contributors to the extraordinary levels of regional biodiversity and endemism found in the North American Coastal Plain Province. These forests require frequent fire return intervals (every 2–3 years) to maintain this rich diversity. In 2009, a floristic inventory was conducted at the Lake Thoreau Environmental Center owned by the University of Southern Mississippi in Hattiesburg, Mississippi. The Center is located on 106 ha with approximately half covered by a 100+ year old longleaf pine forest. When the 2009 survey was conducted, fire had been excluded for over 20 years resulting in a dense understory dominated by woody species throughout most of the forest. The 2009 survey recorded 282 vascular plant species. Prescribed fire was reintroduced in 2009 and reapplied again in 2010, 2012, 2014, 2016, and 2018. A new survey was conducted in 2019 to assess the effects of prescribed fire on floristic diversity. The new survey found an additional 268 species bringing the total number of plants species to 550. This study highlights the changes in species diversity that occurs when fire is reintroduced into a previously fire-suppressed system and the need to monitor sensitive areas for changes in species composition.


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