|Title:||The effect of plasmodiophora brassicae infection, phosphonate and bion treatment on glucosinolate levels in broccoli|
|Authors:||Islam, Md. Nazrul|
Broccoli -- Australia.
|Publisher:||University of Sydney|
Faculty of Agriculture, Food and Natural Resources
|Abstract:||Broccoli (Brassica olerecea L. ssp. italica cv. Marathon) seedlings are a rich source of secondary metabolites including glucosinolates such as 4-methylsulfinylbutyl glucosinolate (glucoraphanin), the precursor of the chemo-protective isothiocyanate, sulforaphane. The aim of this thesis is to investigate the levels of glucosinolate in root and aerial tissues of broccoli following Plasmodiophora brassicae infection and potassium phosphonate and Bion (acibenzolar) treatment under glasshouse condition. Three inoculation techniques of P. brassicae in broccoli seedling were evaluated under glasshouse condition. Combination of spore extraction injected into the root zone and infected gall slurry amended in potting mix exhibited faster and effective disease development than any of the single inoculation method. Field infections of clubroot changed glucosinolate profiles in Brassica rapa ssp.chinensis cv. pak choy. Aliphatic glucosinolate levels were significantly lower in leaf and stem tissues of diseased plants, while indole glucosinolate levels were nearly three times higher in infected root tissues. In the glasshouse trial, the clubroot pathogen Plasmodiophora brassicae affected glucosinolate levels in both root and aerial tissues during primary, secondary and mature gall formation. Total aliphatic glucosinolate levels (glucoiberin, progoitrin, glucoraphanin, gluconapin) remained unchanged in aerial tissues but significantly increased (1.5 times) in root tissues during symptom development (28 days post inoculation). Among aliphatic glucosinolates, glucoraphanin significantly (P<0.05) increased after 28 days in root tissues and 14 days in aerial tissues. Progoitrin IV production also increased both in root and aerial tissues after 28 and 14 days respectively, compared to healthy plants. Total indole glucosinolates (4-hydroxy glucobrassicin, glucobrassicin and neoglucobrassicin) in root tissues increased 2.5 fold during symptom development to mature gall formation stage (21 to 42 days) and also significantly increased (P<0.05) in aerial tissues (1.25 to 2 fold) between primary infection and gall formation. Among indole glucosinolates, glucobrassicin in root tissues increased 8 times during symptom development. Glucosinolate levels and clubroot disease severity were affected by foliar application of potassium phosphonate or Bion. Aliphatic glucosinolate levels in root tissues remained unchanged until 42 days following chemical treatments in both inoculated and uninoculated plants. Combined chemical treatment with phosphonate plus Bion significantly suppressed (PcO.Ol) aliphatic glucosinolate levels in uninoculated plants, however it significantly increased levels in inoculated plants. Indole glucosinolate levels in inoculated root tissues were lower in phosphonate plus Bion treated plants. Bion, or combinations of phosphonate plus Bion, did not affect indole glucosinolate levels, but phosphonate alone significantly (PcO.OOl) increased indole glucosinolate levels in root tissues in uninoculated plants. Aliphatic and indole glucosinolate levels in aerial tissues was lower following chemical treatment in both inoculated or uninoculated plants. Only neoglucobrassicin significantly (PcO.OOl) increased in inoculated plants.|
|Description:||This digital copy has no p.130 as it doesn't exist in the original thesis.|
|Rights and Permissions:||The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.|
|Type of Work:||Masters Thesis|
|Type of Publication:||Doctor of Science in Agriculture D.Sc.Agr.|
|Appears in Collections:||Sydney Digital Theses (Open Access)|
|0000000613068258-IslamMdNazrul_2010.pdf||Thesis||19.96 MB||Adobe PDF|
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