Plant basal resistance - Universiteit Utrecht

More documents

Recommendations

Info

Chapter 1 metabolites are biosynthesised from common amino acids. For example, N-containing alkaloids are usually synthesized from aspartic acid, lysine, tyrosine and tryptophan (Facchini, 2001) These compounds play important roles in plant-pest interactions in different plant families , such as Brassicaceae, Alliaceae and Asteraceae (Burow et al., 2008). Two well-known examples of S- and N-containing defence metabolites are glucosinolates in Brassicaceae and the Alliins in Alliaceae (Burow et al., 2008). S- and N-containing secondary metabolites offer an array of defence compounds that activate direct and/or indirect defences against a broad range of harmful microbes/insects. Oxylipins Oxylipins encompass a large family of oxygenated metabolites that are derived from fatty acids. Oxylipins are best known for their role in plant defence signalling pathways (Blée, 2002), and are produced by oxidation of fatty acids, mainly linolenic acid and linoleic acid, followed by secondary modification (Vicente et al., 2011). The oxylipin biosynthesis pathway converts linoleic acid or linolenic acid into hydroperoxide substrates, such as 9-HPOD (hydroperoxy-octadecadienoic acids), 9-HPOT (hydroperoxy-octadecatrienoic acids), 13- HPOT and 13-HPOD. These compounds are subsequently utilized by different pathway branches that are under control by HPL-hydroperoxide lyase, AOS-allene oxide synthase, DES-divinyl synthase, and P0X-peroxygenase, respectively (Figure 4). The AOS pathway generates the plant defence hormone JA, which is essential for activation of direct and indirect defences against necrotrophic pathogens and insects (Pozo et al., 2005). In addition to jasmonates, the oxylpin pathway produces antimicrobial leaf aldehydes or divinyl ethers and herbivore-induced volatiles, such as green leaf volatiles (Liavonchanka and Feussner, 2006). SECONDARY DEFENCE METABOLITES: FUNCTIONAL CLASSIFICATION The function of secondary metabolites in plant defence ranges from direct to indirect. Metabolites can act directly as anti-proliferative agents for pathogenic microorganisms (González-Lamothe et al., 2009). Secondary metabolites can also act as feeding deterrents against herbivores, during which the metabolites offer a bitter taste, or are directly toxic to the herbivore (Michael, 2003). On the other hand, secondary metabolites can contribute to plant defence indirectly, by stimulating the interaction with disease-suppressing organisms. This form of defence includes certain tritrophic interactions, where herbivore-infested plants emit volatile metabolites that attract natural enemies of the attacking herbivore (Turlings and Ton, 2006). Volatile metabolites also function to attract pollinating insects, which by themselves can have an herbivory-suppressing effect (Tautz and Rostas, 2008). On the basis of their activity, secondary defence metabolites can roughly be 26
27 General introduction divided into three general classes: phytoanticipins and phytoalexins, which contribute to direct defence, and semiochemicals, which function in indirect defence. Phytoanticipins are constitutively produced and are commonly stored in the inactive glycosulated form, whereas phytoalexins are inducible defence metabolites that are synthesised de novo upon pathogen and/or insect attack (VanEtten et al., 1994). As is demonstrated in chapters III and IV of this thesis, some secondary metabolites fulfil multiple tasks in plant defence. Phytoalexins Phytoalexins are low molecular weight secondary metabolites with antimicrobial properties and are synthesized in plants in response to environmental stress. Phytoalexins are widely distributed among crop species, have broad-spectrum antimicrobial effects, and are commonly used as biochemical markers for expression of plant defence (Ahuja et al., 2012). Camalexin (3-thiazol-2-yl-indole) is the major phytoalexins in Arabidopsis and is derived from tryptophan. Depending on attacking pathogen, different signalling pathways are involved in the activation of camalexin biosynthesis (Heck et al., 2003; Denby et al., 2005; Rowe et al., 2010). Camalexin biosynthesis itself is regulated via a MAPK signalling cascade (Ren et al., 2008; Xu et al., 2008). Mao et al., (2011) demonstrated that induction of camalexin is controlled by a MPK3- and MPK6-dependent signalling cascade via phosphorylation of the WRKY33 transcription factor, which in turn binds to the promoter of the camalexin biosynthesis gene PAD3. Camalexin is effective against broad range of biotrophic and necrotrophic fungi and oomycetes (Glazebrook et al., 1997; Van Baarlen et al., 2007; Sanchez- Vallet et al., 2010; Schlaeppi et al., 2010), but is not effective against hemi-biotrophic P. syringae bacteria and generalist insects, such as Myzus persicae and Spodoptera littoralis (Ahuja et al., 2012). While only two phytoalexins are known to be induced by pathogens in Arabidopsis (camalexin and rapalexin A; Pedras and Adio, 2008)), the range of phytoalexins found in crops is typically more diverse. Phytoalexins have been studied in Brassicaceae, Fabaceae, Solanaceae, Vitaceae and Poaceae. The most recent are kauralexins and zealexins from Zea mays (Huffaker et al., 2011; Schmelz et al., 2011). Phytoanticipins In contrast to phytoalexins, which are induced in response to environmental stress, phytoanticipins are present in pre-existing quantities. These low-molecular weight compounds are present either in their active aglycone form, or they are converted into an inactive form by glucosyltransferase activity. Phytoanticipons encompass a diverse group of secondary metabolises and can be annotated to several structural groups, such as terpenoids (e.g. sclareol, episclareol), N- and S-containing metabolites (e.g. benzoxzenone, glucosinolate) and aromatics (e.g. sakuranetin). Some compounds can be classified as both phytoalexins and phytoanticipins, such as the flavanone sakuranetin. This compound is
Page 1 and 2: Plant basal resistance: genetics, b
Page 3 and 4: Most of the research described in t
Page 5: Promotor: Prof. dr. Ir. C.M.J. Piet
Page 10 and 11: 10 CHAPTER 1 General Introduction A
Page 12 and 13: Chapter 1 (PRRs; Gomez-Gomez and Bo
Page 14 and 15: Chapter 1 by avirulent pathogens (R
Page 16 and 17: Chapter 1 Selective non-pathogenic
Page 18 and 19: Chapter 1 an endogenous plant signa
Page 20 and 21: Chapter 1 between defence signallin
Page 22 and 23: Chapter 1 rarely provides complete
Page 24 and 25: Chapter 1 genetic resources for Ara
Page 28 and 29: Chapter 1 constitutively produced i
Page 30: Chapter 1 latest insights. This Cha
Page 33 and 34: ABSTRACT 33 Genetic dissection of b
Page 35 and 36: 35 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 77 and 78:
77 Role of benzoxazinoids in maize
Page 79 and 80:
Page 81 and 82:
Table S1: Primers used for RT-qPCR
Page 83 and 84:
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 94 and 95:
Chapter 4 P. putida is tolerant to
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
Page 106 and 107:
106
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
Page 144 and 145:
Samenvatting inzichten opgeleverd i
Page 146 and 147:
Acknowledgments Acknowledgements In
Page 148 and 149:
Curriculum vitae Shakoor was born o
Page 150:
List of Publications Published arti
show all

Plant basal resistance - Universiteit Utrecht

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?