title: Enhanced seed production under prolonged heat stress conditions in Arabidopsis thaliana plants deficient in cytosolic ascorbate peroxidase 2.
abstract: Reactive oxygen species play a key role in the response of plants to abiotic stress conditions. Their level is controlled in Arabidopsis thaliana by a large network of genes that includes the H(2)O(2)-scavenging enzymes cytosolic ascorbate peroxidase (APX) 1 and 2. Although the function of APX1 has been established under different growth conditions, genetic evidence for APX2 function, as well as for the mode of cooperation between APX1 and APX2, is very limited. This study characterized the response of Arabidopsis mutants deficient in APX1, APX2, and APX1/APX2 to heat, salinity, light, and oxidative stresses. The findings reveal that deficiency in APX2 resulted in a decreased tolerance to light stress, as well as an enhanced tolerance to salinity and oxidative stresses. Interestingly, plants lacking APX2 were more sensitive to heat stress at the seedling stage, but more tolerant to heat stress at the reproductive stage. Cooperation between APX1 and APX2 was evident during oxidative stress, but not during light, salinity, or heat stress. The findings demonstrate a role for APX2 in the response of plants to light, heat, salinity, and oxidative stresses. The finding that plants lacking APX2 produced more seeds under prolonged heat stress conditions suggests that redundant mechanisms activated in APX2-deficient plants during heat stress play a key role in the protection of reproductive tissues from heat-related damage. This finding is very important because heat-associated damage to reproductive tissues in different crops is a major cause for yield loss in agriculture production worldwide.
authors.affiliation: Department of Biological Sciences, College of Arts and Sciences, University of North Texas, 1155 Union Circle #305220, Denton, TX 76203-5017,  USA.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Suzuki
authors.forename: Gad
authors.initials: G
authors.lastname: Miller
authors.forename: Hiroe
authors.initials: H
authors.lastname: Sejima
authors.forename: Jeffery
authors.initials: J
authors.lastname: Harper
authors.forename: Ron
authors.initials: R
authors.lastname: Mittler
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D060387:Ascorbate Peroxidases / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D055786:Gene Knockout Techniques; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000378:metabolism; D008027:Light; D009154:Mutation / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects / Q000528:radiation effects; D036226:Seedlings / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D012639:Seeds / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; D012965:Sodium Chloride; D006861:Hydrogen Peroxide; C555290:APX1 protein, Arabidopsis; C555293:APX2 protein, Arabidopsis; D060387:Ascorbate Peroxidases