Functional analysis of the 1-aminocyclopropane-1-carboxylate deaminase gene of the biocontrol fungus Trichoderma asperellum ACCC30536

Abstract

1-aminocyclopropane-1-carboxylate (ACC) deaminase (ACCD) cleaves ACC, the immediate precursor of the ethylene, decreasing the level of ethylene and inhibition of plant growth resulted by environmental stresses. Here, TaACCD was cloned from the biocontrol agent Trichoderma asperellum ACCC30536. Its open reading frame was 1047 bp long encoding a 37 kD protein of 348 aa, and a pI of 5.77. Phylogenetic analysis demonstrated this protein to be closely related to ACCD from T. asperellum T203 (ACX94231). Transformation of Populus davidiana × P. bolleana with TaACCD, increased salinity tolerance of transgenic plants Pdb-ACCD3 and Pdb-ACCD5. Transgenic plants could survive at salinity of 200 mM NaCl, whereas untransformed control poplar Pdb-NT could withstand salinity to 150 mM NaCl. Transformed plants accumulated higher amounts of chlorophyll compared to Pdb-NT plants. Accumulation of reactive oxygen species (ROS) was regulated by TaACCD under salt stress, as shown from higher superoxide dismutase (SOD) and peroxidase (POD) activities, as well as NBT and DAB staining. Evans blue staining showed that TaACCD maintained membrane integrity in Populus under salt stress conditions. Additionally, TaACCD expression decreased ethylene content of transgenic plants compared to nontransgenic plants, but salt content in plant leaves didnt show obvious difference under same salt concentration. To the best of our knowledge, the current study is the first demonstration that the TaACCD gene from T. asperellum ACCC30536 can enhance tolerance of Populus to salt stress.Key words: Trichoderma asperellum, 1-aminocyclopropane-1-carboxylate deaminase, transgenic poplar, salinity tolerance.Résumé : La 1-aminocyclopropane-1-carboxylate (ACC) désaminase (ACCD) scinde l'ACC, précurseur immédiat de l'éthylène, ce qui réduit la concentration de ce gaz et l'effet inhibiteur qu'il a sur la croissance des plantes soumises à un stress environnemental. Dans le cadre de cette étude, les auteurs ont cloné le gène TaACCD de l'agent de lutte biologique Trichoderma asperellum ACCC30536. Son cadre de lecture ouvert mesure 1 047 pb de longueur et code une protéine de 37 kD composée de 348 acides aminés et d'un pI de 5,77. L'analyse phylogénétique révèle que la protéine est étroitement apparentée à l'ACCD de T. asperellum T203 (ACX94231). La modification de Populus davidiana × P. bolleana avec le gène TaACCD augmente la tolérance des plants transgéniques Pdb-ACCD3 et Pdb-ACCD5 à la salinité. Ces plants survivent à une salinité de 200 mM de NaCl, contre 150 mM de NaCl pour le peuplier témoin non modifié Pdb-NT. Les plants modifiés accumulent plus de chlorophylle que les plants de Pdb-NT. Le gène TaACCD régule l'accumulation des espèces réactives d'oxygène résultant du stress dû au sel, comme l'indique la plus grande activité de la superoxyde dismutase (SOD) et de la peroxydase (POD), de même que la coloration au NBT et au DAB. La coloration au bleu d'Evans révèle que le gène TaACCD aide la membrane cellulaire à garder son intégrité chez Populus, dans de...

Co-cultivation of Trichoderma asperellum GDFS1009 and Bacillus amyloliquefaciens 1841 Causes Differential Gene Expression and Improvement in the Wheat Growth and Biocontrol Activity

“…Thereby, it induces the growth of plant and root under biotic and abiotic stress (Glick, 2014). For the first time, Zhang et al (2016) analyzed the ACC deaminase gene of the biocontrol fungus T. asperellum ACCC30536. In this present investigation, the expression of ACC deaminase was up-regulated in co-cultivation.…”

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