Analysis of the effects of the plant growth promoting substances GR24 and smoke water on abiotically stressed Nicotiana benthamiana seedlings

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Stellenbosch : Stellenbosch University
ENGLISH ABSTRACT: Almost all processes during the life of a plant are affected by the environment. Changes in phytohormone, metabolite and protein levels follow in response to changes in the environment. Plant growth promoting substances can stimulate changes at these levels to facilitate increased plant growth and yields above what the plant would normally establish. In this study, the effects of two growth promoting substances, smoke water (SW) derived from bubbling smoke from the burning of plant material through water, and a synthetic strigolactone analogue, GR24, on plant growth and architecture, as well as the proteome and metabalome of salt stressed Nicotiana benthamiana seedlings were investigated. Physiological studies were conducted to identify the effects of the growth substances on salt stressed seedlings in a tissue culture system. Under non-stress conditions, SW treatment increased seedling fresh mass, root length and leaf area. Under salt stress conditions (100 mM and 150 mM NaCl), SW increased fresh mass, root length, leaf number and lateral root number significantly. Under non-stress conditions, GR24-treated seedlings showed increased fresh mass, leaf number and area and root length. When GR24-treated seedlings were placed under salt stress, the seedlings showed significant increases in fresh mass, leaf number and lateral root number, but only marginal increases in root length and leaf area. Despite these similarities, slight differences were observed in the metabolomes and proteomes of smoke water and GR24-treated seedlings, both with and without the addition of salt stress. Relatively few of the differentially expressed proteins could be identified with the instruments available. Changes in the metabolome indicated that photoassimilation and photosynthesis could be affected in response to smoke water and GR24 treatment. Our results suggest that smoke water and GR24 both promote growth under salt stress conditions in seedlings and we furthermore conclude that, although there are distinct overlaps between treatments, this is accomplished via slightly different mechanisms.
AFRIKAANSE OPSOMMING: Gedurende ‘n plant se lewe word omtrent alle prosesse deur die omgewing geaffekteer. Veranderinge in die omgewing word gevolg deur veranderinge in hormoon, metaboliet en protein vlakke. Plant groei stimulante affekteer hierdie vlakke om plant groei en -opbrengs na bo normalle vlakke te verhoog. In hierdie studie word die effek van twee groei stimulante, rook water verkry deur rook van plant materiaal deur water te borrel en ‘n sintetiese strigolaktoon, GR24, ondersoek op ‘n morfologiese, metaboliese en ‘n proteomiese vlak in Nicotiana benthamiana saailinge. ’n Studie is onderneem om die veranderinge as gevolg van die onderskeie groei stimulante te ondersoek in ‘n weefsel kultuur sisteem. Rook water het onder normale groei omstandighede vars en droeë massa, blaar aantal asook wortel en blaar lengte verhoog. Rook water het na sout behandeling (100 en 150 mM NaCl) steeds vars massa, wortel lengte, blaai aantal en laterale wortel aantal beduidend verhoog in vergelyking met die sout stres kontrole. Behandeling met GR24 het ook vars massa, wortel lengte, blaar aantal en grootte verhoog en onder sout stres met GR24 is ‘n beduidende vergroting opgemerk in vars massa, blaar grootte en laterale wortel aantal. Ongeag van die veranderinge in groei is klein verskille opgemerk in die metaboliet en protein studies. Net ‘n paar proteine kon positief geidentifiseer word met die apparaat beskikbaar. Verandering in die metaboloom wys na veranderinge in fotoassimilasie en fotosintese in reaksie tot rook water en GR24. Hierdie resultate lei tot die gevolgtrekking dat rook water en GR24 beide groei verbeter in saailing behandel met sout en ook dat alhoewel daar sekere ooreenkomste is tussen die reaksies as gevolg van die plant groei stimulante, dit wel geskiet deur geringe verskillende meganismes.
Thesis (MSc)--Stellenbosch University, 2012.
Salt stress, Strigolactone, Smoke water, Plant growth promoting substances, Dissertations -- Plant biotechnology, Theses -- Plant biotechnology, Nicotiana benthamiana