UV–B Radiation – From Environmental Stressor to Regulator of Plant Growth

<p>List of Contributors xv</p>
<p>Preface xix</p>
<p>1 An Introduction to UV B Research in Plant Science 1<br /> Rachana Singh, Parul Parihar, Samiksha Singh, MPVVB Singh, Vijay Pratap Singh and Sheo Mohan Prasad</p>
<p>1.1 The Historical Background 1</p>
<p>1.2 Biologically Effective Irradiance 2</p>
<p>1.3 UV B induced Effects in Plants 3</p>
<p>1.4 Conclusion and Future Prospects 5</p>
<p>Acknowledgements 6</p>
<p>References 6</p>
<p>2 Stimulation of Various Phenolics in Plants Under Ambient UV B Radiation 9<br /> Marija Vidovi , Filis Morina and Sonja Veljovi Jovanovi </p>
<p>2.1 Introduction 9</p>
<p>2.2 UV B Radiation 10</p>
<p>2.2 Phenolics 12</p>
<p>2.2.1 Chemistry of Phenolic Compounds 13</p>
<p>2.2.2 Biosynthesis and Subcellular Localization of Phenolics 13</p>
<p>2.2.3 Functions of Phenolic Compounds Depend on Their Localization 15</p>
<p>2.4 UV B Radiation Stimulates Phenolic Induction 18</p>
<p>2.4.1 Mechanisms of UV B Perception 18</p>
<p>2.4.2 UV B Induced Accumulation of Phenolic Compounds 20</p>
<p>2.4.1 Interactive Effects of UV B with UV A Radiation and PAR on Phenolics Accumulation 28</p>
<p>2.4.2 Interactive Effects of UV B with other Environmental Factors on Phenolics Accumulation 30</p>
<p>2.5 UV B Induced Photomorphological Responses 31</p>
<p>2.5.1 Connection Between UV B Induced Morphological Responses and Phenolics 31</p>
<p>2.5.2 Effect of UV B Radiation on Root Morphology in Relation to Phenolics 32</p>
<p>2.6 Photosynthesis Under UV B Radiation 33</p>
<p>2.6.1 Interplay of Phenolics and Photosynthesis Under UV B Radiation 34</p>
<p>2.7 UV B Radiation Induces Phenolics Accumulation in Fruits 37</p>
<p>2.8 Conclusions and Future Perspectives 38</p>
<p>References 39</p>
<p>3 UV B Radiation: A Reassessment of its Impact on Plants and Crops 57<br /> Krystyna uk Go aszewska</p>
<p>3.1 Introduction 57</p>
<p>3.2 Plant Production 58</p>
<p>3.3 Plant protection Against UVB 60</p>
<p>References 60</p>
<p>4 Interaction of UV B with the Terrestrial Ecosystem 65<br /> Rohit Kumar Mishra, Sanjesh Tiwari and Sheo Mohan Prasad</p>
<p>4.1 Introduction 65</p>
<p>4.2 Growth and Development 66</p>
<p>4.3 Secondary Metabolites 67</p>
<p>4.4 Susceptibility to Herbivorous Insects 67</p>
<p>4.5 Plant Sexual Reproduction 67</p>
<p>4.6 Genomic Level 68</p>
<p>4.7 Conclusion 69</p>
<p>References 70</p>
<p>5 A Review of Stress and Responses of Plants to UV B Radiation 75</p>
<p>Sonika Sharma, Soumya Chatterjee, Sunita Kataria, Juhie Joshi, Sibnarayan Datta, Mohan G. Vairale and Vijay Veer</p>
<p>5.1 Introduction 75</p>
<p>5.2 Morphological and Yield Response to UV B 76</p>
<p>5.3 Targets of UV B in the Carbon Fixation Cycle 79</p>
<p>5.4 Photoreceptors and Signalling Pathway in Response to UV B Radiation 80</p>
<p>5.5 Acclimatization and Protection in Response to UV B 82</p>
<p>5.6 Oxidative Stress and Antioxidant System in Response to UV B 82</p>
<p>5.7 DNA Damage and Repair Mechanism 83</p>
<p>5.8 Exclusion of UV Components: Experimental Approach to Study the Effect on Plants 85</p>
<p>5.9 Conclusion and Future Prospective 86</p>
<p>Acknowledgement 87</p>
<p>References 87</p>
<p>6 Oxidative Stress and Antioxidative Defence System in Plants in Response to UV B Stress 99<br /> Sunita Kataria</p>
<p>6.1 Introduction 99</p>
<p>6.2 Plant Protection Against UV Radiation 101</p>
<p>6.3 UV B and ROS 103</p>
<p>6.4 UV B and Antioxidant Enzymes 104</p>
<p>6.5 UV B and Antioxidant 107</p>
<p>6.6 UV B and Signalling 108</p>
<p>6.7 Conclusions and Perspectives 110</p>
<p>References 111</p>
<p>7 Major influence on phytochrome and photosynthetic machinery under UV B exposure 123<br /> Anita Singh, Gausiya Bashri and Sheo Mohan Prasad</p>
<p>7.1 Introduction 123</p>
<p>7.2 Photomorphogenesis in Higher Plants 124</p>
<p>7.2.1 Phytochrome system and its interaction with UV B 124</p>
<p>7.2.2 Photomorphogenic responses of UV B 125</p>
<p>7.2.3 UV B signal transduction (UV R8) 127</p>
<p>7.3 Effect of UV B Exposure on Photosynthetic Machinery 128</p>
<p>7.3.1 Direct effects of UV B on photosynthetic machinery 128</p>
<p>7.3.1.1 Effects of UV B stress on components involved in light reaction 128</p>
<p>7.3.1.2 Effect of UV B stress on photosystems and cytochrome b6/f complex 129</p>
<p>7.3.2 Indirect effect of UV B stress on components involved in dark reaction 132</p>
<p>7.3.2.1 Impact on regulation of stomata and RuBisCO enzyme 132</p>
<p>7.3.3 UV B induced ROS production in plants 133</p>
<p>7.3.4 Protective adaptation 133</p>
<p>7.4 Conclusion and Future Perspectives 135</p>
<p>References 136</p>
<p>8 UV B Radiation Induced Damage of Photosynthetic Apparatus of Green Leaves: Protective Strategies vis a vis Visible and/or UV A Light 143<br /> Padmanava Joshi</p>
<p>8.1 Introduction 143</p>
<p>8.2 UV B Effects on the Photosynthetic Apparatus of Leaves 143</p>
<p>8.3 UV A Effects on Photosynthetic Apparatus of Leaves (Damage and Promotion) 145</p>
<p>8.4 UV A Mediated Modulation of UV B Induced Damage 145</p>
<p>8.5 PAR Mediated Balancing of UV B Induced Damage 146</p>
<p>8.6 Photosynthetic Adaptation and Acclimation to UV B Radiation 146</p>
<p>8.7 Corroboration with Sensible Approach 147</p>
<p>8.8 Conclusion 149</p>
<p>Acknowledgements 149</p>
<p>References 149</p>
<p>9 Ultraviolet Radiation Targets in the Cellular System: Current Status and Future Directions 155</p>
<p>Parul Parihar, Rachana Singh, Samiksha Singh, MPVVB Singh, Vijay Pratap Singh and Sheo Mohan Prasad</p>
<p>9.1 Introduction 155</p>
<p>9.2 Absorption Characteristics of Biomolecules 156</p>
<p>9.3 Action Spectrum 156</p>
<p>9.4 Targets of UV B 157</p>
<p>9.4.1 Interaction with Biomolecules 157</p>
<p>9.4.2 Nucleic Acids 158</p>
<p>9.4.3 Ribonucleic Acids 159</p>
<p>9.5 UV B Interaction with Proteins 159</p>
<p>9.5.1 Tryptophan 160</p>
<p>9.5.2 Tyrosine 160</p>
<p>9.5.3 Phenylalanine 162</p>
<p>9.5.4 Histidine 162</p>
<p>9.6 The Photosynthetic Machinery 163</p>
<p>9.6.1 Photosystem I and II 164</p>
<p>9.6.2 The Light Harvesting Complexes 165</p>
<p>9.7 Cell Division and Expansion 167</p>
<p>9.8 Conclusion and Future Directions 168</p>
<p>Acknowledgements 169</p>
<p>References 169</p>
<p>10 Silicon: A Potential Element to Combat Adverse Impact of UV B in plants 175<br /> Durgesh Kumar Tripathi, Shweta, Shweta Singh, Vaishali Yadav, Namira Arif, Swati Singh, Nawal Kishor Dubey and Devendra Kumar Chauhan</p>
<p>10.1 Introduction 175</p>
<p>10.2 The role of Silicon Against UV B Exposure on Morphology of Plants 178</p>
<p>10.3 The defensive role of silicon against UV B exposure on physiological and biochemical traits of plants 179</p>
<p>10.4 Silicon repairs anatomical structures of plants damaged by UV B exposures 180</p>
<p>10.5 UV B induced oxidative stress and silicon supplementation in plants 181</p>
<p>10.6 Silicon supplementation and the status of antioxidant enzymes in plants exposed to UV B 183</p>
<p>10.7 Silicon and level of phenolic compounds under UV B stress 184</p>
<p>10.8 Present status and future prospectives 186</p>
<p>References 187</p>
<p>11 Sun Screening Biomolecules in Microalgae: Role in UV Photoprotection 197<br /> Rajesh P Rastogi, Ravi R Sonani, Aran Incharoensakdi and Datta Madamwar</p>
<p>11.1 Introduction 197</p>
<p>11.2 Global Climate Change and UV Radiation 198</p>
<p>11.3 Effects of UV Radiation on Microalgae 199</p>
<p>11.4 UV induced Defence Mechanisms 201</p>
<p>11.5 Sun Screening Biomolecules as Key UV Photoprotectants 201</p>
<p>11.5.1 Mycosporine Like Amino Acids (MAAs) 202</p>
<p>11.5.2 Scytonemin 204</p>
<p>11.6 UV Induced Biosynthesis 206</p>
<p>11.7 Photoprotective Function 207</p>
<p>11.8 Conclusions 208</p>
<p>Acknowledgements 208</p>
<p>References 208</p>
<p>12 Plant Response: UB B Avoidance Mechanisms 217<br /> Sunil K Gupta, Marisha Sharma, Farah Deeba and Vivek Pandey</p>
<p>12.1 Introduction 217</p>
<p>12.2 Ultraviolet Radiation: Common Source, Classification and Factors 219</p>
<p>12.2.1 Common Sources of UV R 219</p>
<p>12.2.2 Classification 219</p>
<p>12.2.3 Environmental Factors Affecting UV Level 220</p>
<p>12.3 UV B and Human Health 220</p>
<p>12.3.1 Effects on the Skin 220</p>
<p>12.3.2 Effects on the Eyes 220</p>
<p>12.4 UV B and Plant Responses 220</p>
<p>12.4.1 Morphological Responses 220</p>
<p>12.4.1.1 Visible Symptoms 220</p>
<p>12.4.1.2 Plant Growth and Leaf Phenology 221</p>
<p>12.4.1.3 Reproductive Morphology 222</p>
<p>12.4.1.4 UV B induced photomorphogenesis 222</p>
<p>12.4.2 Leaf Ultrastructure and Anatomy 222</p>
<p>12.4.3 Crop Yield 223</p>
<p>12.4.4 Photosynthesis 225</p>
<p>12.4.4.1 Pigments 225</p>
<p>12.4.4.2 Photosynthetic Machinery 225</p>
<p>12.4.5 Biochemical Responses 226</p>
<p>12.4.5.1 ROS Production in Plants 226</p>
<p>12.4.5.2 Free Radical Scavenging Mechanism 227</p>
<p>12.4.6 Molecular Responses 227</p>
<p>12.4.6.1 UV B and Genes 227</p>
<p>12.4.6.2 UV and Proteins 230</p>
<p>12.5 UV B Avoidance and Defence Mechanism 234</p>
<p>12.5.1 Avoidance at Morphological Level 234</p>
<p>12.5.1.1 Epicuticular Waxes 234</p>
<p>12.5.2 Avoidance at Biochemical Level 235</p>
<p>12.5.2.1 Possible Role of Pectin Endocytosis in UV B Avoidance 235</p>
<p>12.5.3 Avoidance at the Molecular Level 236</p>
<p>12.5.3.1 DNA Repair 236</p>
<p>12.5.3.2 Genes and Avoidance 237</p>
<p>12.5.3.3 UV B perceived by UVR8 Strongly Inhibits Shade Avoidance 237</p>
<p>12.5.4 UV B and Secondary Metabolites 238</p>
<p>12.5.4.1 Plant Phenolics 238</p>
<p>12.5.4.2 Anthocyanin 239</p>
<p>12.5.4.3 Alkaloids 240</p>
<p>12.5.4.4 Isoprenoids 240</p>
<p>12.5.4.5 Glucosinolates 240</p>
<p>12.6 UV B and its Significance 240</p>
<p>12.6.1 Ecological Significance 240</p>
<p>12.6.2 UV B and Plant Competition 241</p>
<p>12.7 Conclusion 242</p>
<p>Acknowledgments 243</p>
<p>References 244</p>
<p>13 Impact of UV B Exposure on Phytochrome and Photosynthetic Machinery: From Cyanobacteria to Plants 259<br /> Shivam Yadav, Alok Kumar Shrivastava, Chhavi Agrawal, Sonia Sen, Antra Chatterjee, Shweta Rai and LC Rai</p>
<p>13.1 Introduction 259</p>
<p>13.2 Effect of UV B Irradiation on Photosynthetic Machinery of Cyanobacteria 260</p>
<p>13.2.1 Pigments 260</p>
<p>13.2.2 Photosynthetic Electron Transport System 261</p>
<p>13.2.3 Photophosphorylation and CO2 fixation 262</p>
<p>13.3 Effect of UV B Irradiation on Photosynthetic Machinery of Algae 262</p>
<p>13.4 Effect of UV B Irradiation on Photosynthetic Machinery of Higher Plants 264</p>
<p>13.4.1 Pigments 264</p>
<p>13.4.1.1 Phytochrome 264</p>
<p>13.4.1.2 Chlorophylls, carotenoids and other pigments 265</p>
<p>13.4.2 Photosystem II 265</p>
<p>13.4.2.1 Oxygen evolving complex 266</p>
<p>13.4.2.2 Plastoquinones and redox active tyrosines 266</p>
<p>13.4.2.3 D1 and D2 proteins 267</p>
<p>13.4.3 Photosystem I 267</p>
<p>13.4.4 Cytochrome B6F complex, ATP synthase and RuBisCO 267</p>
<p>13.4.5 Net photosynthesis 268</p>
<p>13.5 Conclusion and future perspective 268</p>
<p>Acknowledgements 268</p>
<p>References 269</p>
<p>14 Discovery of UVR8: New Insight in UV B Research 279<br /> ShivamYadav and Neelam Atri</p>
<p>14.1 Introduction 279</p>
<p>14.2 Photoperception in Plants 280</p>
<p>14.3 Discovery of UVR8: UV B Photoreceptor 280</p>
<p>14.4 UVR8 Structure 281</p>
<p>14.4.1 Salt Bridge Interactions Mediate UVR8 Dimerization 281</p>
<p>14.4.2 Chromophore and Key Tryptophan Residues 281</p>
<p>14.5 Physiological Roles of UVR8 283</p>
<p>14.5.1 Photomorphogenic Response Regulation by UVR8 283</p>
<p>14.5.2 Regulation of Flavonoid Biosynthesis 284</p>
<p>14.5.3 Plant Pathogen and Plant Herbivore Interactions 284</p>
<p>14.6 Conclusion and Future Perspectives 284</p>
<p>References 285</p>
<p>15 UVR8 Signalling, Mechanism and Integration with other Pathways 289<br /> Antra Chatterjee, Alok Kumar Shrivastava, Sonia Sen, Shweta Rai, Shivam Yadav and LC Rai</p>
<p>15.1 Introduction 289</p>
<p>15.2 UVR8 Arbitrated Signalling 290</p>
<p>15.2.1 Constitutively Photomorphogenic 1 (COP1) 290</p>
<p>15.2.2 Elongated Hypocotyl 5 (HY5) and HYH 291</p>
<p>15.2.3 Repressor of UV B Photomorphogenesis 1 (RUP1) and RUP2 292</p>
<p>15.3 Molecular Mechanism of Photoreceptor Mediated Signalling 293</p>
<p>15.4 UVR8 Involvements in Different Pathways 296</p>
<p>15.4.1 Protection from Photo Inhibition and Photo Oxidative Stress 297</p>
<p>15.4.2 Flavonoid and Alkaloid Pathways 298</p>
<p>15.4.3 DNA Damage Repair 299</p>
<p>15.4.4 Defence Against Pathogens 299</p>
<p>15.4.5 Inhibition of Plant Shade Avoidance 300</p>
<p>15.4.6 Regulation of Leaf Morphogenesis 300</p>
<p>15.4.7 Regulation of Root Growth and Development 300</p>
<p>15.4.8 Circadian Clock 301</p>
<p>15.5 Conclusion and Future Perspectives 301</p>
<p>Acknowledgements 302</p>
<p>References 302</p>
<p>Index 309</p>