Plant basal resistance - Universiteit Utrecht

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Chapter 4 P. putida is tolerant to DIMBOA To examine the effect of DIMBOA on plant-beneficial rhizobacterial growth, we assessed in vitro growth of P. putida KT2440 bacteria in the presence of increasing concentrations of DIMBOA. P. putida KT2440 displayed similar growth rates up to 0.5 mM DIMBOA. By contrast, DIMBOA strongly affected growth rates of the ubiquitous soil bacterium A. tumefaciens (Agrios, 1997), effects were already apparent at 0.01 mM and became proportionally stronger at 0.1 and 0.5 mM DIMBOA (Figure 2A). Hence, P. putida KT2440 appears relatively tolerant to DIMBOA in comparison to other soil bacteria. For all subsequent experiments, DIMBOA was employed at concentrations of 5 μg mL -1 (0.023 mM). This relatively low concentration has no detrimental effect on P. putida growth (Figure 2A) and is quantitatively consistent with our root exudation experiments (Figure 1). Figure 2: Tolerance of P. putida KT2440 to DIMBOA. A. In vitro growth of P. putida KT2440 is not affected up to 0.5 mM DIMBOA, whereas the ubiquitous soil bacterium A. tumefaciens is increasingly affected at concentrations of 0.01 mM DIMBOA and above. Growth was quantified by determining average OD 600 values (n = 5). B. In the presence of P. putida KT2440, DIMBOA degradation is significantly accelerated, whereas accumulation of MBOA is significantly reduced. Shown are best fitting polynomial regressions ± 99% confidence intervals. DIMBOA and MBOA quantities are expressed as relative peak areas (HPLC-DAD), normalised to DIMBOA peak areas at the start of each experiment. 94
P. putida accelerates DIMBOA breakdown 95 Recruitment of beneficial bacteria by maize roots To study whether the observed tolerance of P. putida KT2440 to DIMBOA is based on BX catabolism, we studied the effect of P. putida KT2440 on stability of DIMBOA and its direct break-down product, 6-methoxy-benzoxazolin-2-one (MBOA). In two independent experiments, DIMBOA concentrations were consistently reduced at a significantly greater rate, whereas MBOA accumulation was significantly reduced in the presence of P. putida bacteria (Figure 2B). These results demonstrate that P. putida KT2440 accelerates breakdown of DIMBOA. The reduced accumulation of MBOA in the presence of P. putida could be explained by an even faster metabolic break-down of this compound, but could also suggest DIMBOA degradation via products other than MBOA. Although is not possible to distinguish which of these processes is responsible for the observed compound dynamics in the presence of P. putida, our results clearly show that P. putida has the metabolic capacity to metabolise DIMBOA and reduce overall BXs quantities in its environment. Figure 3: Functional annotation of 55 DIMBOA-inducible genes of P. putida KT2440 at 1 hour after application of 5 µg mL -1 DIMBOA to the growth medium. Whole-genome transcriptome analysis was based on P. putida KT2440-specific cDNA microarrays, accommodating results from three independent experiments.
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Plant basal resistance: genetics, b
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Most of the research described in t
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Promotor: Prof. dr. Ir. C.M.J. Piet
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10 CHAPTER 1 General Introduction A
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Chapter 1 (PRRs; Gomez-Gomez and Bo
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Chapter 1 by avirulent pathogens (R
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Chapter 1 Selective non-pathogenic
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Chapter 1 an endogenous plant signa
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Chapter 1 between defence signallin
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Chapter 1 rarely provides complete
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Chapter 1 genetic resources for Ara
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Chapter 1 metabolites are biosynthe
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Chapter 1 constitutively produced i
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Chapter 1 latest insights. This Cha
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ABSTRACT 33 Genetic dissection of b
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35 Genetic dissection of basal defe
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Page 43 and 44: 43 Genetic dissection of basal defe
Page 45 and 46: Natural variation in responsiveness
Page 57: 57 Genetic dissection of basal defe
Page 61 and 62: ABSTRACT 61 Role of benzoxazinoids
Page 63 and 64: 63 Role of benzoxazinoids in maize
Page 67 and 68: Chemical treatments and callose qua
Page 69 and 70: Aphid infestation stimulates apopla
Page 81 and 82: Table S1: Primers used for RT-qPCR
Page 86 and 87: 86 CHAPTER 4 Benzoxazinoids in root
Page 88 and 89: Chapter 4 INTRODUCTION Plants have
Page 90 and 91: Chapter 4 Our study presents eviden
Page 92 and 93: Chapter 4 Maize - P. putida FBC004
Page 96 and 97: Chapter 4 Impact of DIMBOA on the P
Page 98 and 99: Chapter 4 PP5286 dut deoxyuridine 5
Page 100 and 101: Chapter 4 DIMBOA-producing wild-typ
Page 102 and 103: Chapter 4 DISCUSSION The rhizospher
Page 104 and 105: Chapter 4 patterns, we considered t
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Page 108 and 109: 108 CHAPTER 5 General Discussion
Page 110 and 111: Chapter 5 QTL was caused by a polym
Page 112 and 113: Chapter 5 Figure 1: CYP81D11 regula
Page 114 and 115: Chapter 5 et al., 2009), and allele
Page 116 and 117: Chapter 5 defence against different
Page 118 and 119: Chapter 5 occurred at time-points l
Page 120 and 121: Chapter 5 rhizospheric signals that
Page 122 and 123: Chapter 5 glucosinolate profiles. 1
Page 124 and 125: References References Abramovitch R
Page 126 and 127: References QTL mapping and characte
Page 128 and 129: References Gianoli E, Niemeyer HM (
Page 130 and 131: References Kliebenstein DJ, Kroyman
Page 132 and 133: References Studies in Natural Produ
Page 134 and 135: References Geniostoma antherotrichu
Page 136 and 137: References Todesco M, Balasubramani
Page 138 and 139: References Walters DR, Paterson L,
Page 140 and 141: Summary Summary Basal resistance in
Page 142 and 143: Samenvatting Samenvatting Basale re
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Samenvatting inzichten opgeleverd i
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Acknowledgments Acknowledgements In
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Curriculum vitae Shakoor was born o
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List of Publications Published arti
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