Long‐Term Field Drought Affects Leaf Protein Pattern and Chloroplast Ultrastructure of Winter Wheat in a Cultivar‐Specific Manner

Abstract

Recurrent drought periods of varying duration often cause extensive crop damage and affect wheat production in Southern Europe. This study compares biochemical and ultrastructural responses of four wheat (Triticum aestivum L.) cultivars to long-term field drought, and their contribution to final grain yield. Gel electrophoresis and immunoblotting analyses combined with transmission electron microscopy and grain yield evaluation were employed to assess drought susceptibility of the wheat cultivars. Two of them behaved as droughttolerant, the other two presented as drought sensitive. Enhanced degradation of Rubisco large subunit (RLS), Rubisco small subunit (RSS) and Rubisco activase (RA) accompanied by an increased protease activity and reduced levels of heat shock proteins (HSP70) and dehydrins (DHNs) were associated with drought sensitivity. Drought tolerance coincided with relatively stable or increased HSP70 and DHN contents, and unchanged/higher levels of RLS, RSS and RA. Sensitive cultivars were more vulnerable to ultrastructural damages, showing obvious degradation of chloroplast membrane systems and depletion of leaf starch reserves. These drought responses affected yield potential, as tolerant cultivars gave higher yield under intense drought. Thus, our results provide additional insights into the complexity of plant drought responses, identifying multiple interacting traits that may serve as indirect selection criteria for wheat drought tolerance.

Drought stress and carbon assimilation in a warming climate: Reversible and irreversible impacts

“…The response of different genotypes of the same crop species to drought or heat periods may vary in wide range (Vassileva et al, 2009(Vassileva et al, , 2011(Vassileva et al, , 2012Erice et al, 2010Erice et al, , 2011Yin et al, 2010 ;Parry et al, 2011;Prior et al, 2011;Cao et al, 2014 ;Habash et al, 2014;Topbjerg et al, 2014;Acuna-Galinda et al, 2015 ;Lopes et al, 2015;Wani et al, 2015;Wehner et al, 2015). This is the basis for breeding of crop varieties with a better performance under abiotic stresses.…”

Application of chlorophyll fluorescence performance indices to assess the wheat photosynthetic functions influenced by nitrogen deficiency

“…The differences between the PI trends found in the youngest leaf (leaf 1) and old leaf (leaf 3) represent a nice example of the effects of nitrogen redistribution on photosynthetic performance, which was dominant in plants poorly supplied with nitrogen. After emergence of the spike, the nitrogen can be re-distributed also from leaves, as disassembly of photosynthetic apparatus under stress conditions can be a valuable source of nitrogen for the grain (Vassileva et al 2012).…”

Measurements of chlorophyll fluorescence in different leaf positions may detect nitrogen deficiency in wheat

“…This, in fact, influences the results of photosynthetic measurements in N-deficient plants in two ways: (i) the moderate nitrogen deficiency will have only minor effects at the level of the top leaf, as it is sufficiently supplied by redistributed nitrogen, and (ii) the photosynthetic capacity of lower leaf positions could be strongly reduced. It is even more complicated in later developmental stages of cereals, as after emergence of the head the nitrogen can be re-distributed also from leaves into the spike, as disassembly of photosynthetic apparatus under stress conditions can be a valuable source of nitrogen for the grain (Vassileva et al, 2012). Therefore, in addition to measurements in the youngest leaf positions, we also measured the third leaf from the top.…”