Bioassays to evaluate the resistance of whole plants to the herbivorous insect thrips

Thrips are tiny, cell-content–feeding insects that are a major pest on crops and ornamentals. Besides causing direct feeding damage, thrips may also cause indirect damage by vectoring tospoviruses. Novel resistance mechanisms to thrips need to be discovered and validated. Induction of jasmonic acid–dependent defenses has been demonstrated to be essential for resistance to thrips, but underlying mechanisms still need to be discovered. For this, it is vital to use robust plant-thrips assays to analyze plant defense responses and thrips performance. In recently developed high-throughput phenotyping platforms, the feeding damage that is visible as silver spots, and the preference of thrips in a two-choice setup is assessed, using leaf discs. Here, we describe whole-plant thrips assays that are essential for (1) validation of findings obtained by the leaf disc assays, (2) assessment of longer-term effects on thrips feeding success and fecundity, (3) determination of spatial-temporal effects induced by primary thrips infestation on a secondary attack by thrips or other insects or pathogens, and (4) assessment of gene expression and metabolite changes. We present detailed methods and tips and tricks for (a) rearing and selection of thrips at different developmental stages, (b) treatment of the whole plant or an individual leaf with thrips, and (c) determination of feeding damage and visualization of thrips oviposition success in leaves

Bioassays to evaluate the resistance of whole plants to the herbivorous insect thrips

Thrips are tiny, cell-content–feeding insects that are a major pest on crops and ornamentals. Besides causing direct feeding damage, thrips may also cause indirect damage by vectoring tospoviruses. Novel resistance mechanisms to thrips need to be discovered and validated. Induction of jasmonic acid–dependent defenses has been demonstrated to be essential for resistance to thrips, but underlying mechanisms still need to be discovered. For this, it is vital to use robust plant-thrips assays to analyze plant defense responses and thrips performance. In recently developed high-throughput phenotyping platforms, the feeding damage that is visible as silver spots, and the preference of thrips in a two-choice setup is assessed, using leaf discs. Here, we describe whole-plant thrips assays that are essential for (1) validation of findings obtained by the leaf disc assays, (2) assessment of longer-term effects on thrips feeding success and fecundity, (3) determination of spatial-temporal effects induced by primary thrips infestation on a secondary attack by thrips or other insects or pathogens, and (4) assessment of gene expression and metabolite changes. We present detailed methods and tips and tricks for (a) rearing and selection of thrips at different developmental stages, (b) treatment of the whole plant or an individual leaf with thrips, and (c) determination of feeding damage and visualization of thrips oviposition success in leaves

Breeding Cold-Tolerant Crops

Low-temperature stress is considered as the major abiotic constraint limiting plant\u2019s growth and the potential land cultivation. Crop adaptation to limiting temperature is thus an important breeding objective because it determines yield stability in environment-friendly cultivation practices. Conventional breeding methods had limited success in improving the cold tolerance of important crop plants because of the complexity of stress tolerance traits, low genetic variance, and lack of efficient selection criteria. The knowledge of physiology, of genetics, and of the DNA technology has improved substantially nowadays, and these advancements will allow the breeder to predict the breeding value of best genotypes by using physiology, genetics, and molecular information. The perspective for selecting more effectively cold-tolerant crops will involve efficient genotyping, reliable phenotyping and envirotyping, and adequate statistical models

Abiotic and Biotic Stresses Interaction in Fabaceae Plants. Contributions from the Grain Legumes/Soilborne Vascular Diseases/Drought Stress Triangle

Editors: Mirza Hasanuzzaman, Susana Araújo, Sarvajeet Singh Gill.As sessile organisms, plants are constantly exposed to simultaneously abiotic and biotic stresses that impact growth thus resulting in significant yield losses. An example is drought and root infecting pathogens, which combined cause greater damage to plants than the stresses individually. Substantial information is available on the physiological, molecular, and metabolic changes in Fabaceae plants exposed to individual stresses, but little is known about how plants respond to multiple stresses. This is of primary importance for the development of breeding approaches based on the trade-off between plant defense response mechanisms, and high and consistent yield under field conditions. A better knowledge of the mechanisms by which legume plants perceive and transduce simultaneous or sequential combination of stress signals to initiate diverse adaptive responses is essential for breeding multiple stress-tolerant crop cultivars. In this chapter, we assess the relevance of understanding legume combined responses to abiotic and biotic stresses for production and breeding, focusing on soilborne vascular diseases and drought interaction in grain legumes. Particular attention is given to the crosstalk between signaling pathways of the “stress triangle” pathogen/host/environment interactions and to the application of integrated breeding methods aiming at multiple stress-resistant legume crops better adapted to climate change.Financial support by Fundação para a Ciência e Tecnologia (FCT), Portugal, is acknowledged through grant SFRH/BD/92160/2013 (STL), DL57 PhD holder contract (SA), IF/01337/2014 FCT Investigator contract (MCVP), research project BeGeQA (PTDC/AGR-TEC/3555/2012) and research unit GREEN-IT “Bioresources for Sustainability” (UID/Multi/04551/2019)

Genomic Designing for Climate-Smart Tomato

Tomato is the first vegetable consumed in the world. It is grown in very different conditions and areas, mainly in field for processing tomatoes while fresh-market tomatoes are often produced in greenhouses. Tomato faces many environmental stresses, both biotic and abiotic. Today many new genomic resources are available allowing an acceleration of the genetic progress. In this chapter, we will first present the main challenges to breed climate-smart tomatoes. The breeding objectives relative to productivity, fruit quality, and adaptation to environmental stresses will be presented with a special focus on how climate change is impacting these objectives. In the second part, the genetic and genomic resources available will be presented. Then, traditional and molecular breeding techniques will be discussed. A special focus will then be presented on ecophysiological modeling, which could constitute an important strategy to define new ideotypes adapted to breeding objectives. Finally, we will illustrate how new biotechnological tools are implemented and could be used to breed climate-smart tomatoes