Exploiting Genetic and Genomic Resources to Enhance Heat-Tolerance in Tomatoes

Valentino Ruggieri,Amalia Barone,Carlo Schettini,Luigi Frusciante,Fabrizio Olivieri,Roberta Calafiore,Maria Manuela Rigano

doi:10.3390/agronomy9010022

Valentino Ruggieri, Amalia Barone + Show 5 more

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https://doi.org/10.3390/agronomy9010022

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Abstract

High temperature is one of the most detrimental abiotic stresses in tomatoes. Many studies highlighted that even small increases in temperature can alter the plant reproductive system, causing a significant reduction in tomato yield. The aim of this study was to exploit the phenotypic and genomic variations of a tomato landrace collection grown at high temperatures. Fifteen genotypes were selected as the best performing in two experimental fields. The selection was based on six yield-related traits, including flower earliness, number of flowers per inflorescence, fruit set, number of fruit per plant, fruit weight and yield per plant. In order to identify markers targeting traits that could be highly influenced by adverse climate conditions, such as flowering and fruit setting, an association mapping approach was undertaken exploiting a tomato high-throughput genomic array. The phenotypic variability observed allowed us to identify a total of 15 common markers associated with the studied traits. In particular, the most relevant associations co-localized with genes involved in the floral structure development, such as the style2.1 gene, or with genes directly involved in the response to abiotic stresses. These promising candidate genes will be functionally validated and transferred to a cultivated tomato to improve its performance under high temperatures.

Highlights

Global climate change and growing food demand have become two of the major challenges faced by humans in the last few years
If no association was detected for a trait in one of the two trials, associations with a higher p-value were further explored. We considered both the kinship matrix based on the single nucleotide polymorphism (SNP) data and the population structure covariates detected by the Different databases were exploited to find candidate genes related to flowering mechanisms and heat stress
High temperatures during flowering of crops normally used for human consumption may have a large impact on global food production, and this effect will likely increase in the coming years because of the expected climatic changes

Summary

Introduction

Global climate change and growing food demand have become two of the major challenges faced by humans in the last few years. The predicted increase of global warming [1,2] poses a large risk for crop productivity and imposes the urgent development of strategies to substantially improve food availability. High temperature is a major abiotic stress compromising productivity and stability of several crops, mostly due to the modification of plant life cycle stages. This is a consequence of the alteration of a number of basic molecular processes, such as protein folding, maintenance of membrane stability, photosynthesis and assimilate metabolism [3]. Plants possess various mechanisms to ensure survival under elevated temperatures, even a small temperature increase (1.5 ◦ C) can have a significant impact on the processes related to reproductive development, negatively affecting fruit set and crop yield [4]. Heat-induced yield reduction was documented in many cultivated crops including cereals (e.g., rice, wheat, barley, sorghum and, maize), pulses

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