Identification of metabolites involved in heat stress response in different tomato genotypes

Abstract

Propositions1. Since tomato pollen is sensitive to temperature variations, results from climate chamber experiments with controlled temperature cannot be extrapolated to pollen thermotolerance in commercial tomato production.(this thesis)2. The pollen isolation protocol is a critical determinant for the success of pollen metabolomics studies.(this thesis)3. The choice of the p-value has an undesirably strong influence on a study's conclusions.4. Nutrition should be considered as the first medicine. MeatlessMonday is an effective policy to reduce global warming.6. The health of science rests on scientist's honesty. If Dutch were not Dutch but French, most of them would not speak EnglishPropositions belonging to the thesis, entitled Contents ___________________________________________________________________________ Chapter 1General introduction 1 Chapter 2The metabolic basis of pollen thermo-tolerance: Perspectives for breeding 13 Chapter 3The effect of isolation methods of tomato pollen on the results of metabolic profiling 39 Chapter 4Untargeted metabolomic analysis of tomato pollen development and heat stress response 63 Chapter 5Screening for pollen tolerance to high temperatures in tomato 83 Chapter 6Metabolites associated with thermo-tolerance of tomato pollen 95 Chapter 7General discussion 133 References Climate changeClimate is unequivocally changing. In 2014, IPCC released the fifth assessment report on climate change and stated that "the atmosphere and ocean have warmed, the amounts of snow and ice have diminished and sea level has risen" (IPCC 2014). The main cause for this global warming is extremely likely to be due to anthropogenic activities that are widely acknowledged by climate specialists (Cook et al. 2013). Heat waves and extreme temperatures are expected to be more frequent and to last longer (Meehl and Tebaldi 2004). This climate change is expected to affect the world of today in many ways, including the extinction of species that cannot escape their environment and a decrease in food productivity. For instance, the well documented heat wave of 2003 in Europe led to a yield loss of 25% and 21% for maize and wheat in France, respectively, with an overall economic loss in the European Union estimated at 13 billion euros (IPCC 2007). The direct effect on the human population is not to be underestimated, especially if one takes into account that the world population is predicted to rise from 7.3 billion up to 11 billion by the middle of the 21 st century, thus alarming the decision-makers (Porter and Semenov 2005). From the reduction of greenhouse gas emission with the Kyoto protocol (Oberthur and Hermann 1999) to the recent COP21 agreement to limit the temperature increase of 2˚C (Iyer et al. 2015), policymakers mull over mitigation options. A synergy of policies and adaptation strategies may enhance the efficacy to respond to climate change and limit the consequences on living organisms and ecosystems. The adaption of crops is nested in the identification of genotypes tolerant to temperature...

Past and Future of Plant Stress Detection: An Overview From Remote Sensing to Positron Emission Tomography

“…In recent years, metabolism reprogramming under heat stress has been extensively studied in several agricultural crops, i.e., wheat (Thomason et al, 2018 ; Wang et al, 2018a , c ) and soybeans (Das et al, 2017 ), among others. Tomato microspore of pollen after 2 h of heat stress increased significantly the total abundance of flavonoids (Paupiére, 2017 ); pepper plants coped with heat stress inducing the accumulation of osmotic adjusting materials such as total soluble sugars, proline and total protein as well as flavonoids (isorhamnetin-3-O-neohesperidoside, daidzein, 7-O-methyleriodicty-ol, tulipanin) (Wang et al, 2019b ). Heat-stress was often studied in combination with other environmental stressful conditions, such as elevated CO2, reproducing the climate change scenario, as for maize (Qu et al, 2018a ) and soybeans, among others.…”