Postharvest Physiology & Technology of Fruits
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What is Stress? Dose-Response Effects in Commonly Used In Vitro Stress Assays

What is Stress? Dose-Response Effects in Commonly Used In Vitro Stress Assays | Postharvest Physiology & Technology of Fruits | Scoop.it

"We found that the commonly used stress-inducing agents mannitol, sorbitol, NaCl and H2O2 impact shoot growth in a highly specific and dose-dependent way. Therefore, shoot growth is a sensitive, relevant and easily measured phenotype to assess stress tolerance over a wide range of stress levels."


Via Mary Williams, R K Upadhyay
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Mary Williams's curator insight, April 12, 2014 4:32 AM

Often students use Arabidopsis seedlings in the teaching lab to learn about plant physiology. This paper shows that shoot growth is sensitive parameter to quantify even mild stress.

Rescooped by Renato Dantas from Plant-Microbe Symbiosis
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AM Fungi - Biological Controls for Preventing Food Deterioration: Strategies for Pre- and Postharvest Management

AM Fungi - Biological Controls for Preventing Food Deterioration: Strategies for Pre- and Postharvest Management | Postharvest Physiology & Technology of Fruits | Scoop.it

Soil is a reservoir of an unseen world pulsating with life. Some of these soil organisms are beneficial while others may prove harmful. Microorganisms that adversely affect plant growth and health are pathogenic fungi, oomycetes, bacteria and nematodes. More than 800 million people do not have adequate food; 1.3 billion live on less than $1 a day and at least 10% of global food production is lost to plant disease. Soil-borne plant pathogens are also more recalcitrant to management and control compared to pathogens that attack the aerial portions of the plant. In the last century, the green revolution technologies such as pesticides, synthetic fertilizers and high yielding cultivars were used to overcome these constraints, which resulted in increased natural degradation, raising questions about the sustainability of current agricultural practices. The challenge for the next 50 years is to double food production in a way that does not compromise environmental integrity and public health. One of the answers is AMF: arbuscular mycorrhizae fungi. Various aspects of AMF and AMF associations are discussed in the chapter. The multitude of beneficial effects exhibited by AMF on the health of the plants makes them priceless and a valuable association. AMF associations are therefore an eco-friendly answer to the control of plant pathogens which would otherwise require the heavy use of chemicals, which pollute the environment.


Via Jean-Michel Ané
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Novel Roles for the Polyphenol Oxidase Enzyme in Secondary Metabolism and the Regulation of Cell Death in Walnut

Novel Roles for the Polyphenol Oxidase Enzyme in Secondary Metabolism and the Regulation of Cell Death in Walnut | Postharvest Physiology & Technology of Fruits | Scoop.it

The enzyme polyphenol oxidase (PPO) catalyzes the oxidation of phenolic compounds into highly reactive quinones. Polymerization of PPO-derived quinones causes the postharvest browning of cut or bruised fruit, but the native physiological functions of PPOs in undamaged, intact plant cells are not well understood. Walnut (Juglans regia) produces a rich array of phenolic compounds and possesses a single PPO enzyme, rendering it an ideal model to study PPO. We generated a series of PPO-silenced transgenic walnut lines that display less than 5% of wild-type PPO activity. Strikingly, the PPO-silenced plants developed spontaneous necrotic lesions on their leaves in the absence of pathogen challenge (i.e. a lesion mimic phenotype). To gain a clearer perspective on the potential functions of PPO and its possible connection to cell death, we compared the leaf transcriptomes and metabolomes of wild-type and PPO-silenced plants. Silencing of PPO caused major alterations in the metabolism of phenolic compounds and their derivatives (e.g. coumaric acid and catechin) and in the expression of phenylpropanoid pathway genes. Several observed metabolic changes point to a direct role for PPO in the metabolism of tyrosine and in the biosynthesis of the hydroxycoumarin esculetin in vivo. In addition, PPO-silenced plants displayed massive (9-fold) increases in the tyrosine-derived metabolite tyramine, whose exogenous application elicits cell death in walnut and several other plant species. Overall, these results suggest that PPO plays a novel and fundamental role in secondary metabolism and acts as an indirect regulator of cell death in walnut.

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Current Biology: Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold (2013)

Current Biology: Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold (2013) | Postharvest Physiology & Technology of Fruits | Scoop.it

Shelf life is an important quality trait for many fruit, including tomatoes. We report that enrichment of anthocyanin, a natural pigment, in tomatoes can significantly extend shelf life. Processes late in ripening are suppressed by anthocyanin accumulation, and susceptibility to Botrytis cinerea, one of the most important postharvest pathogens, is reduced in purple tomato fruit. We show that reduced susceptibility to B. cinerea is dependent specifically on the accumulation of anthocyanins, which alter the spreading of the ROS burst during infection. The increased antioxidant capacity of purple fruit likely slows the processes of overripening. Enhancing the levels of natural antioxidants in tomato provides a novel strategy for extending shelf life by genetic engineering or conventional breeding.


Via Kamoun Lab @ TSL, Renato Dantas
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fundoshi's curator insight, June 20, 2013 4:05 AM

殺生だからインパクトに関係ないなんてことはないだろうな。

Rescooped by Renato Dantas from Plants and Microbes
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Current Biology: Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold (2013)

Current Biology: Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold (2013) | Postharvest Physiology & Technology of Fruits | Scoop.it

Shelf life is an important quality trait for many fruit, including tomatoes. We report that enrichment of anthocyanin, a natural pigment, in tomatoes can significantly extend shelf life. Processes late in ripening are suppressed by anthocyanin accumulation, and susceptibility to Botrytis cinerea, one of the most important postharvest pathogens, is reduced in purple tomato fruit. We show that reduced susceptibility to B. cinerea is dependent specifically on the accumulation of anthocyanins, which alter the spreading of the ROS burst during infection. The increased antioxidant capacity of purple fruit likely slows the processes of overripening. Enhancing the levels of natural antioxidants in tomato provides a novel strategy for extending shelf life by genetic engineering or conventional breeding.


Via Kamoun Lab @ TSL
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fundoshi's curator insight, June 20, 2013 4:05 AM

殺生だからインパクトに関係ないなんてことはないだろうな。