Identification of Discriminant Factors after Exposure of Maize and Common Bean Plantlets to Abiotic Stresses

Lázaro Hernández,Leyanes Díaz-López,José Carlos Lorenzo,Octavio Loyola-González,Oscar Vicente,Bárbara Valle,Lourdes Yabor,Julia Martínez,Carlos Aragón,Jutta Papenbrock,Richard Trethowan

doi:10.15835/nbha4329916

Abstract

Adverse environmental conditions limit crop yield and better understanding of plant response to stress will assist the development of more tolerant cultivars. Maize and common bean plantlets were evaluated under salinity, high temperature, drought and waterlogged conditions to identify biochemical markers which could be useful for rapid identification of putative stress tolerant plants. The levels of phenolics (free, cell wall-linked, total), aldehydes including malondialdehyde andchlorophylls (a, b, total) were measured on stressed plantlets. Only two indicators were statistically non-significant: chlorophyll b in maize plantlets stressed with sodium chloride and malondialdehyde content in drought stressed maize. The most remarkable effects of abiotic stresses can be summarized as follows: (i) salinity increased levels of free phenolics in maize plantlets and chlorophylls (a, b, total) in common bean; (ii) high temperature (40 °C) elevated levels of chlorophylls (a, b, total) in maize but decreased chlorophylls (a, b, total) and free phenolics in common bean; (iii) drought increased phenolics and decreased chlorophylls (a, b, total) in maize and increased chlorophyll pigments (a, b, total) in common bean; (iv) waterlogging increased free phenolics and decreased chlorophylls (a, b, total) in maize and increased chlorophyll (a, total) incommon bean. Free phenolics and chlorophylls, especially a, were the most responsive indicators to stress and can, therefore, be considered putative biochemical markers for abiotic stress tolerance in maize and common bean. The use of Fisher’s linear discriminant analysis to differentiate non-stressed and stressed plants in breeding programs is also a novel aspect of this report. Fisher’s linear discriminant functions classified correctly 100% of non-stressed or stressed originally grouped plants.

Highlights

Adverse environmental conditions, such as salinity, high temperature, drought and waterlogging, limit the geographical distribution of plant species and crop yield (Osmond et al, 1987)
Free phenolics tended to increase in maize under stress whereas chlorophylls decreased, under drought and waterlogging
Chlorophyll increased in maize while free phenolics decreased in common bean

Summary

Introduction

Adverse environmental conditions, such as salinity, high temperature, drought and waterlogging, limit the geographical distribution of plant species and crop yield (Osmond et al, 1987). Population growth and the importance of sustainable food production makes the development of stress tolerant crop cultivars a high-priority globally (Zhu, 2001). Maize is the second most important agricultural crop globally. It is a human and livestock food and used in the processing of industrial goods (Qing et al, 2009). Global maize production in 2011 exceeded 700 million tons (FAOSTAT, 2013). Legumes play a critical role in human and animal diets and contribute to sustainability by maintaining soil fertility (Tilman et al, 2002). Common bean (Phaseolus vulgaris L.), one of the world’s most important grain legumes, is consumed as a dietary staple worldwide, in Latin America and Africa (FAOSTAT, 2013)

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