September 2015, Volume 57 Issue 9, Pages 734每806.


Cover Caption: Microtubules in Shade Avoidance
When plants such as Arabidopsis are under canopy shade, the most prominent response is the elongations of stems/petioles. In this issue, Yu et al. (pp. 757每769) report that shade avoidance 2 (sav2) mutant (the bottom one in two SEM photos, and the right one in two seedlings) exhibits short and swollen hypocotyls when grown in shade. SAV2 encodes a 汕-tubulin, suggesting cMTs is cortical in regulating anisotropic cell growth.

 

          Cell and Developmental Biology
Expression of auxin synthesis gene tms1 under control of tuber-specific promoter enhances potato tuberization in vitro  
Author: Oksana O. Kolachevskaya, Valeriya V. Alekseeva, Lidiya I. Sergeeva, Elena B. Rukavtsova, Irina A. Getman, Dick Vreugdenhil, Yaroslav I. Buryanov and Georgy A. Romanov
Journal of Integrative Plant Biology 2015 57(9): 734每744
Published Online: November 24, 2014
DOI: 10.1111/jipb.12314
      
    

Phytohormones, auxins in particular, play an important role in plant development and productivity. Earlier data showed positive impact of exogenous auxin on potato (Solanum tuberosum L.) tuberization. The aim of this study was to generate potato plants with increased auxin level predominantly in tubers. To this end, a pBinB33-tms1 vector was constructed harboring the Agrobacterium auxin biosynthesis gene tms1 fused to tuber-specific promoter of the class I patatin gene (B33-promoter) of potato. Among numerous independently generated B33:tms1 lines, those without visible differences from control were selected for detailed studies. In the majority of transgenic lines, tms1 gene transcription was detected, mostly in tubers rather than in shoots. Indoleacetic acid (IAA) content in tubers and the auxin tuber-to-shoot ratio were increased in tms1-expressing transformants. The organ-specific increase in auxin synthesis in B33:tms1-transformants accelerated and intensified the process of tuber formation, reduced the dose of carbohydrate supply required for in vitro tuberization, and decreased the photoperiodic dependence of tuber initiation. Overall, a positive correlation was observed between tms1 expression, IAA content in tubers, and stimulation of tuber formation. The revealed properties of B33:tms1 transformants imply an important role for auxin in potato tuberization and offer prospects to magnify potato productivity by a moderate organ-specific enhancement of auxin content.

 

Kolachevskaya OO, Alekseeva VV, Sergeeva LI, Rukavtsova EB, Getman IA, Vreugdenhil D, Buryanov YI, Romanov GA (2015) Expression of auxin synthesis gene tms1 under control of tuberspecific promoter enhances potato tuberization in vitro. J Integr Plant Biol 57: 734–744. doi: 10.1111/jipb.12314

Abstract (Browse 1277)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Potato plants were transformed with pBinB33-tms1 vector assuring predominant expression of auxin synthesis gene in tubers. B33:tms1-transformants showed accelerated and intensified in vitro tuberization with reduced dependence on photoperiod and carbohydrate supply. Our data imply an important role for auxin in potato tuberization and offer prospects to magnify potato productivity.
Characterization and molecular cloning of a serine hydroxymethyltransferase 1 (OsSHM1) in rice
Author: Dekai Wang, Heqin Liu, Sujuan Li, Guowei Zhai, Jianfeng Shao and Yuezhi Tao
Journal of Integrative Plant Biology 2015 57(9): 745每756
Published Online: January 31, 2015
DOI: 10.1111/jipb.12336
      
    

Serine hydroxymethyltransferase (SHMT) is important for one carbon metabolism and photorespiration in higher plants for its participation in plant growth and development, and resistance to biotic and abiotic stresses. A rice serine hydroxymethyltransferase gene, OsSHM1, an ortholog of Arabidopsis SHM1, was isolated using map-based cloning. The osshm1 mutant had chlorotic lesions and a considerably smaller, lethal phenotype under natural ambient CO2 concentrations, but could be restored to wild type with normal growth under elevated CO2 levels (0.5% CO2), showing a typical photorespiratory phenotype. The data from antioxidant enzymes activity measurement suggested that osshm1 was subjected to significant oxidative stress. Also, OsSHM1 was expressed in all organs tested (root, culm, leaf, and young panicle) but predominantly in leaves. OsSHM1 protein is localized to the mitochondria. Our study suggested that molecular function of the OsSHM1 gene is conserved in rice and Arabidopsis.

 

Wang D, Liu H, Li S, Zhai G, Shao J, Tao Y (2015) Characterization and molecular cloning of a serine hydroxymethyltransferase 1 (OsSHM1) in rice. J Integr Plant Biol 57:745–756 doi: 10.1111/jipb.12336

Abstract (Browse 850)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
OsSHM1, an ortholog of Arabidopsis SHM1 in rice, was cloned and characterized. The osshm1 mutant showed a typical photorespiratory phenotype and was subjected to significant oxidative stress. Insight into the specific details of the photorespiratory pathway in rice will be beneficial to reduce photorespiration and enhance rice productivity.
Characterization of tub4P287L, a 汕-tubulin mutant, revealed new aspects of microtubule regulation in shade  
Author: Jie Yu, Hong Qiu, Xin Liu, Meiling Wang, Yongli Gao, Joanne Chory and Yi Tao
Journal of Integrative Plant Biology 2015 57(9): 757每769
Published Online: April 21, 2015
DOI: 10.1111/jipb.12363
      
    
When sun plants, such as Arabidopsis thaliana, are under canopy shade, elongation of stems/petioles will be induced as one of the most prominent responses. Plant hormones mediate the elongation growth. However, how environmental and hormonal signals are translated into cell expansion activity that leads to the elongation growth remains elusive. Through forward genetic study, we identified shade avoidance2 (sav2) mutant, which contains a P287L mutation in β-TUBULIN 4. Cortical microtubules (cMTs) play a key role in anisotropic cell growth. Hypocotyls of sav2 are wild type-like in white light, but are short and highly swollen in shade and dark. We showed that shade not only induces cMT rearrangement, but also affects cMT stability and dynamics of plus ends. Even though auxin and brassinosteroids are required for shade-induced hypocotyl elongation, they had little effect on shade-induced rearrangement of cMTs. Blocking auxin transport suppressed dark phenotypes of sav2, while overexpressing EB1b-GFP, a microtubule plus-end binding protein, rescued sav2 in both shade and dark, suggesting that tub4P287L represents a unique type of tubulin mutation that does not affect cMT function in supporting cell elongation, but may affect the ability of cMTs to respond properly to growth promoting stimuli.
 

Yu J, Qiu H, Liu X, Wang M, Gao Y, Chory J, Tao Y (2015) Characterization of tub4P287L, a b-tubulin mutant, revealed new aspects of microtubule regulation in shade. J Integr Plant Biol 57: 757–769 doi: 10.1111/jipb.12363

Abstract (Browse 886)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Cortical microtubules (cMTs) play a key role in anisotropic cell growth. We found both the organization patterns and dynamics of cMTs are altered in shade. P287 residue in TUB4 is critical for microtubule stability and regulation, which may affect the ability of cMTs to respond properly to growth promoting stimuli.
          Metabolism and Biochemistry
Expressing an (E)-汕-farnesene synthase in the chloroplast of tobacco affects the preference of green peach aphid and its parasitoid
Author: Gen-Ping Wang, Xiu-Dao Yu, Jia Fan, Cheng-She Wang and Lan-Qin Xia
Journal of Integrative Plant Biology 2015 57(9): 770每782
Published Online: December 12, 2014
DOI: 10.1111/jipb.12319
      
    

(E)-β-Farnesene (EβF) synthase catalyses the production of EβF, which for many aphids is the main or only component of the alarm pheromone causing the repellence of aphids and also functions as a kairomone for aphids' natural enemies. Many plants possess EβF synthase genes and can release EβF to repel aphids. In order to effectively recruit the plant-derived EβF synthase genes for aphid control, by using chloroplast transit peptide (CTP) of the small subunit of Rubisco (rbcS) from wheat (Triticum aestivum L.), we targeted AaβFS1, an EβF synthase gene from sweet wormwood (Artemisia annua L.), to the chloroplast of tobacco to generate CTP+AaβFS1 transgenic lines. The CTP+AaβFS1 transgenic tobacco plants could emit EβF at a level up to 19.25 ng/day per g fresh tissues, 4–12 fold higher than the AaβFS1 transgenic lines without chloroplast targeting. Furthermore, aphid/parasitoid behavioral bioassays demonstrated that the CTP+AaβFS1 transgenic tobacco showed enhanced repellence to green peach aphid (Myzus persicae) and attracted response of its parasitoid Diaeretiella rapae, thus affecting aphid infestation at two trophic levels. These data suggest that the chloroplast is an ideal subcellular compartment for metabolic engineering of plant-derived EβF synthase genes to generate a novel type of transgenic plant emitting an alarm pheromone for aphid control.

 

Wang GP, Yu XD, Fan J, Wang CS, Xia LQ (2015) Expressing an (E)-b-farnesene synthase in the chloroplast of tobacco affects the preference of green peach aphid and its parasitoid. J Integr Plant Biol 57: 770–782 doi: 10.1111/jipb.12319

Abstract (Browse 930)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
(E)-汕-farnesene (E汕F) is the main component of the aphid alarm pheromones, and also functions as a kairomone in attracting aphids* predators and parasitoids. Expressing E汕F synthase in tobacco chloroplast could be an effective strategy for aphid control through continuously emitting E汕F to repel aphids and attract aphids* enemies.
          Plant-environmental Interactions
Genome-wide identification, expression analysis of auxin-responsive GH3 family genes in maize (Zea mays L.) under abiotic stresses
Author: Shangguo Feng, Runqing Yue, Sun Tao, Yanjun Yang, Lei Zhang, Mingfeng Xu, Huizhong Wang and Chenjia Shen
Journal of Integrative Plant Biology 2015 57(9): 783每795
Published Online: December 30, 2014
DOI: 10.1111/jipb.12327
      
    

Auxin is involved in different aspects of plant growth and development by regulating the expression of auxin-responsive family genes. As one of the three major auxin-responsive families, GH3 (Gretchen Hagen3) genes participate in auxin homeostasis by catalyzing auxin conjugation and bounding free indole-3-acetic acid (IAA) to amino acids. However, how GH3 genes function in responses to abiotic stresses and various hormones in maize is largely unknown. Here, the latest updated maize (Zea mays L.) reference genome sequence was used to characterize and analyze the ZmGH3 family genes from maize. The results showed that 13 ZmGH3 genes were mapped on five maize chromosomes (total 10 chromosomes). Highly diversified gene structures and tissue-specific expression patterns suggested the possibility of function diversification for these genes in response to environmental stresses and hormone stimuli. The expression patterns of ZmGH3 genes are responsive to several abiotic stresses (salt, drought and cadmium) and major stress-related hormones (abscisic acid, salicylic acid and jasmonic acid). Various environmental factors suppress auxin free IAA contents in maize roots suggesting that these abiotic stresses and hormones might alter GH3-mediated auxin levels. The responsiveness of ZmGH3 genes to a wide range of abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses.

 

Feng S, Yue R, Tao S, Yang Y, Zhang L, Xu M, Wang H, Shen C (2015) Genome-wide identification, expression analysis of auxinresponsive GH3 family genes in maize (Zea mays L.) under abiotic stresses. J Integr Plant Biol 57: 783–795 doi: 10.1111/jipb.12327

Abstract (Browse 1401)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Thirteen ZmGH3 genes were characterized and analyzed from maize (Zea mays L.). The responsiveness of ZmGH3 genes to various abiotic stresses and stress-related hormones suggested that ZmGH3s are involved in maize tolerance to environmental stresses. Various environmental factors affect the growth of maize by altering GH3-mediated auxin levels.
Arabidopsis PED2 positively modulates plant drought stress resistance  
Author: Haitao Shi, Tiantian Ye, Fan Yang and Zhulong Chan
Journal of Integrative Plant Biology 2015 57(9): 796每806
Published Online: January 15, 2015
DOI: 10.1111/jipb.12330
      
    

Abscisic acid (ABA) is an important phytohormone that functions in seed germination, plant development, and multiple stress responses. Arabidopsis Peroxisome defective 2 (AtPED2) (also known as AtPEXOXIN14, AtPEX14), is involved in the intracellular transport of thiolase from the cytosol to glyoxysomes, and perosisomal matrix protein import in plants. In this study, we assigned a new role for AtPED2 in drought stress resistance. The transcript level of AtPED2 was downregulated by ABA and abiotic stress treatments. AtPED2 knockout mutants were insensitive to ABA-mediated seed germination, primary root elongation, and stomatal response, while AtPED2 over-expressing plants were sensitive to ABA in comparison to wide type (WT). AtPED2 also positively regulated drought stress resistance, as evidenced by the changes of water loss rate, electrolyte leakage, and survival rate. Notably, AtPED2 positively modulated expression of several stress-responsive genes (RAB18, RD22, RD29A, and RD29B), positively affected underlying antioxidant enzyme activities and negatively regulated reactive oxygen species (ROS) level under drought stress conditions. Moreover, multiple carbon metabolites including amino acids, organic acids, sugars, sugar alcohols, and aromatic amines were also positively regulated by AtPED2. Taken together, these results indicated a positive role for AtPED2 in drought resistance, through modulation of stress-responsive genes expression, ROS metabolism, and metabolic homeostasis, at least partially.

 

Shi H, Ye T, Yang F, Chan Z (2015) Arabidopsis PED2 positively modulates plant drought stress resistance. J Integr Plant Biol 57: 796–806 doi: 10.1111/jipb.12330

Abstract (Browse 1212)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Arabidopsis Peroxisome defective 2 (AtPED2) is involved in the intracellular transport of thiolase from the cytosol to glyoxysomes, and perosisomal matrix protein import in plants. This study shows the positive role for AtPED2 in drought resistance, through modulation of ABA sensitivity, stress-responsive genes expression, ROS metabolism, and metabolic homeostasis.
 

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