Effect of Mi-1.2 gene in Natal Host Plants on Behavior and Biology of the Tomato Psyllid Bactericerca cockerelli (Sulc) (Hemiptera: Psyllidae)

2007 ◽  
Vol 42 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Clare L. Casteel ◽  
Linda L. Walling ◽  
Timothy D. Paine

The Mi-1.2 gene has been isolated from wild varieties of tomato, Solanum peruvianum (Mill), and incorporated into near isogenic commercial varieties of tomato, Solanum lycopersicon. Plants containing the gene confer resistance to tomato psyllid, Bactericerca cockerelli (Sulc), as well as species of aphids, whiteflies, and nematodes. Considering bias in host preference and oviposition responses based on early adult experience is well documented in the literature; the objective of this study was to determine if the presence or absence of the Mi-1.2 in the rearing host influenced subsequent host selection, oviposition, and development time. The results presented here show that the host that psyllids developed on did not affect subsequent selection of host for oviposition, but incidence of oviposition was higher on plants that did not contain the Mi-1.2 gene [Moneymaker (mi-1.2)] compared to plants with the Mi-1.2 gene [Motelle (Mi-1.2)]. Psyllid nymph survival and development time did not differ between plant varieties. Consequently, plants containing the gene may be useful components to IPM programs to control the tomato psyllid.

2011 ◽  
Vol 66 (11-12) ◽  
pp. 621-626
Author(s):  
Shixiang Zong ◽  
Zhizheng Wang ◽  
Youqing Luo ◽  
Jingtong Zang ◽  
Junbao Wen

We determined the mechanisms underlying host selection by adults of the seabuckthorn carpenterworm, Holcocerus hippophaecolus Hua, Chou, Fang et Chen. Four sea buckthorn (Hippophae rhamnoides L.) subspecies (varieties) with different degrees of resistance to H. hippophaecolus were chosen for artificial insect infection in cages. The results showed that olfactory and visual cues are very important for the selection of host plants by H. hippophaecolus, but that olfactory stimuli play a more vital role in this process. The relative abundance of branches and leaves had no effect on the likelihood that adults landed on plants from four subspecies (varieties), but did influence landing rates within the same subspecies (varieties). When considering only the most resistant sea buckthorn subspecies (varieties), the presence of luxuriant branches and leaves led to lower landing rates. These results provide a theoretical basis for the understanding of H. hippophaecolus damage to sea buckthorn and the means to implement effective measures of control


Author(s):  
Ruo Sun ◽  
Xingcong Jiang ◽  
Michael Reichelt ◽  
Jonathan Gershenzon ◽  
Daniel Giddings Vassão

AbstractThe cabbage aphid Brevicoryne brassicae is a notorious agricultural pest that specializes on plants of the Brassicaceae family, which are chemically defended by glucosinolates. By sequestering glucosinolates from its host plants and producing its own activating enzyme (myrosinase), this aphid employs a self-defense system against enemies paralleling that in plants. However, we know little about the metabolic fate of individual glucosinolates during aphid sequestration and activation and about the biochemical effects of this defense on aphid enemies. Here, we probed these questions focusing on B. brassicae and a predatory lacewing, Chrysoperla carnea. We found that distinct glucosinolates were accumulated by B. brassicae at different rates, with aliphatic glucosinolates being taken up more quickly than indolic ones. B. brassicae myrosinase enzymatic activities toward different glucosinolates were strongly correlated to their rates of accumulation in vivo. Surprisingly, after simulated predation, the production of toxic isothiocyanate products (ITCs) was quantitatively outweighed by less toxic products such as nitriles and ITC-conjugates. Nevertheless, the defensive cocktails significantly impaired C. carnea development. Tissue-specific quantification of glucosinolate metabolites revealed that the lacewings employ both conjugation and mobilization to reduce the toxicity of aliphatic ITCs, but these strategies were only partially effective. These results clarify the metabolic fates of glucosinolates after sequestration by an aphid herbivore and further in a higher trophic level, as well as the consequences for predator survival and development, and might be instructive for integrative pest management approaches targeting the cabbage aphid.


Parasitology ◽  
1995 ◽  
Vol 111 (4) ◽  
pp. 531-536 ◽  
Author(s):  
A. Saul

SUMMARYA stochastic simulation model of the transmission and maintenance of genetic heterogeneity in the absence and presence of external selection pressures is presented for polygamous intestinal helminths such as Ascaris. The model assumes that the density distribution of the adult parasites is highly aggregated and that density-dependent effects on fecundity are important. The model gives rise to stable infection rates in the host. Where the parasite population contains genetic heterogeneity, with the exception of stochastic fluctuations which models genetic drift, the ratio of the different alleles remained constant over extended periods of time. This result contrasts with that of an earlier analytical model (Anderson, R. M., May, M. R. & Gutpa S. (1989) Parasitology 99, S59–S79), in which uneven mating probabilities for the different combinations of worm possible in a host was postulated to inevitably lead to fixation of the most abundant allele. New results suggest that in spite of the restricted choice of mating available to a worm in the confines of a host, selection pressure always leads to enrichment of the parasites carrying resistant alleles.


2010 ◽  
Vol 63 ◽  
pp. 275-275
Author(s):  
A.J. Puketapu

The tomato/potato psyllid Bactericera cockerelli (Sulc) (Hemiptera Triozidae) is an introduced pest of solanaceous crops in New Zealand A range of established plants play host to Bactericera cockerelli including three traditional Maori food sources taewa or Maori potatoes (Solanum tuberosum ssp andigena) kumara (Ipomoea batatas) and poroporo (Solanum aviculare) Taewa and kumara are highly susceptible to summer B cockerelli infestation whilst poroporo an evergreen plant remains susceptible yearround and provides overwintering refuge Extensive monitoring of each host plant was carried out to determine the significance of each host in the lifecycle of B cockerelli in New Zealand Poroporo was monitored from late autumn for 6 months to determine if the plant served as a significant overwintering host for the pest after harvesting summer crops Taewa and kumara plants were monitored throughout the summer growing season on a weekly basis increasing to twice a week as populations proliferated Host plants were monitored both in the natural environment and under laboratory conditions Data collected contributed to tracking population development of B cockerelli on each host including the length of each life stage (ie egg nymph adult) Comparisons between the three hosts revealed host preference host suitability and the significance of each host in the lifecycle progression of B cockerelli


2020 ◽  
Vol 5 (4(73)) ◽  
pp. 12-18
Author(s):  
G.T. Bekmirzaev ◽  
I.A. Begmatov ◽  
D.B. Yulchiev

The purpose of the experimental study was the selection of salt tolerant crops and the search for useful horticultural species for growing them on saline lands. The experimental study was conducted at the University of Algarve, Portugal, in a greenhouse. The following vegetable crops were selected for research: lettuce (Lactuca sativaL), New Zealand spinach (Tetragonia tetragonioides) and garden purslane (Portulaca oleracea). Experimental results showed that New Zealand spinach and garden purslane have high potential as species resistant to high salt content and are therefore recommended for cultivation in order to reduce soil salinity. The above crops, mainly New Zealandspinach, are good types of garden crops with high useful qualities and productivity. Therefore, it has been shown that this method is a clean and environmentally friendly tool to prevent salinization and maintain the sustainability of agricultural systems


2021 ◽  
Author(s):  
Nivedita Nivedita ◽  
John D. Aitchison ◽  
Nitin S. Baliga

ABSTRACTDrug resistance is a major problem in treatment of microbial infections and cancers. There is growing evidence that a transient drug tolerant state may precede and potentiate the emergence of drug resistance. Therefore, understanding the mechanisms leading to tolerance is critical for combating drug resistance and for the development of effective therapeutic strategy. Through laboratory evolution of yeast, we recently demonstrated that adaptive prediction (AP), a strategy employed by organisms to anticipate and prepare for a future stressful environment, can emerge within 100 generations by linking the response triggered by a neutral cue (caffeine) to a mechanism of protection against a lethal agent (5-FOA). Here, we demonstrate that mutations selected across multiple laboratory evolved lines had linked the neutral cue response to core genes of autophagy. Across these evolved lines, conditional activation of autophagy through AP conferred tolerance, and potentiated subsequent selection of mutations in genes specific to overcoming the toxicity of 5-FOA. We propose a model to explain how extensive genome-wide genetic interactions of autophagy facilitates emergence of AP over short evolutionary timescales to potentiate selection of resistance-conferring mutations.


2020 ◽  
Vol 12 (1) ◽  
pp. 11-34
Author(s):  
Iva Klepić ◽  
Mirela Mabić ◽  
Danijela Madžar

In modern business conditions, human resources have become the most important resource of enterprises, and many authors point out that this is especially true for SMEs, in which, due to their specificity, human resources create a competitive advantage of the company and affect its survival and development. SMEs are faced with a strong, global competition of large enterprises and in order to survive and grow in the market, they must find specific strengths within themselves, develop and use them. Creativity is one of the most powerful tools that enable SMEs competitiveness, survival and development in the market. The basic objective of this research is to determine whether there is a correlation between recruitment and selection of human resources and organizational creativity in SMEs. The survey was conducted in SMEs in the Federation of B&H in 2019. An original questionnaire was created for the research, which collected the opinion of top managers on the recruitment and selection of human resources and organizational creativity in small and medium-sized enterprises. Data have been analysed using IBM SPSS Statistic 25.0. From the statistical procedures, the following were used: Shapiro-Wilk's test, Pearson's coefficient of correlation, Mann-Whitney U test and t-test for independent samples. The results of the survey showed that there is a correlation between the recruitment and selection of human resources and organizational creativity in SMEs and that there are differences in the correlation between the recruitment and selection of human resources and organizational creativity in the enterprises in terms of their size.


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