title: Resilience of Penicillium resedanum LK6 and exogenous gibberellin in improving Capsicum annuum growth under abiotic stresses.
abstract: Understanding how endophytic fungi mitigate abiotic stresses in plants will be important in a changing global climate. A few endophytes can produce phytohormones, but their ability to induce physiological changes in host plants during extreme environmental conditions are largely unexplored. In the present study, we investigated the ability of Penicillium resedanum LK6 to produce gibberellins and its role in improving the growth of Capsicum annuum L. under salinity, drought, and heat stresses. These effects were compared with exogenous application of gibberellic acid (GA3). Endophyte treatment significantly increased shoot length, biomass, chlorophyll content, and the photosynthesis rate compared with the uninfected control during abiotic stresses. The endophyte and combined endophyte + GA3 treatments significantly ameliorated the negative effects of stresses compared with the control. Stress-responsive endogenous abscisic acid and its encoding genes, such as zeaxanthin epoxidase, 9-cis-epoxycarotenoid dioxygenase 3, and ABA aldehyde oxidase 3, were significantly reduced in endophyte-treated plants under stress. Conversely, salicylic acid and biosynthesis-related gene (isochorismate synthase) had constitutive expressions while pathogenesis related (PR1 and PR5) genes showed attenuated responses during endophyte treatment under abiotic stresses. The present findings suggest that endophytes have effects comparable to those of exogenous GA3; both can significantly increase plant growth and yield under changing environmental conditions by reprogramming the host plant's physiological responses.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea, latifepm78@yahoo.co.uk.
authors.forename: Abdul Latif
authors.initials: AL
authors.lastname: Khan
authors.forename: Muhammad
authors.initials: M
authors.lastname: Waqas
authors.forename: In-Jung
authors.initials: IJ
authors.lastname: Lee
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D002212:Capsicum / Q000235:genetics / Q000254:growth & development / Q000382:microbiology* / Q000502:physiology*; D055864:Droughts; D060026:Endophytes / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D005875:Gibberellins / Q000494:pharmacology*; D006358:Hot Temperature; D010407:Penicillium / Q000502:physiology*; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D054712:Salinity; D013312:Stress, Physiological
chemical_list: D005875:Gibberellins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D000040:Abscisic Acid; C007842:gibberellic acid