Memory of wheat to repeated Heat Stress during pre-anthesis could be responsible for improved tolerance

• Pages: 1-21

1

Balkan Journal of

Interdisciplinary Research

E-ISSN 2411-9725

ISSN 2410-759X

Vol.10 No.3

December, 2024

Research Article

© 2024 Ariola Bacu, Krisida Ciko & Vjollca Ibro

This is an open access article licensed under the Creative Commons

Aribution-NonCommercial 4.0 International License

(hps://creativecommons.org/licenses/by-nc/4.0/)

Memory of wheat to repeated Heat Stress during pre-anthesis could be

responsible for improved tolerance

Ariola Bacu

Department of Biotechnology, Faculty of Natural Sciences, University of Tirana, Albania

Krisida Ciko

Laboratory of Mycotoxins, Department of Toxicology and Veterinary Drug Residues, Food

Safety and Veterinary Institute, Albania

Vjollca Ibro

Department of Agronomy Sciences, Agricultural University of Tirana, Tirana, Albania

DOI: hps://doi.org/10.2478/bjir-2024-0021

Abstract

Risk imposed by high temperatures (HT) to the quality and yield of cereals, requires evaluation

of naturally resistant resources, and nding of methods to improve it. In this research, were

analyzed the tolerance to HT of 19 winter wheat cultivars (Triticum aestivum L.) in use in

Albania, and the possible memory gained to the repeated stress, before anthesis. Biometric

(root, shoot, leafs length), physiological (ne root cells death, Relative Water Content-RWC),

and biochemical parameters (chla, chlb, carotenoids and xantophylls, and total carbohydrates)

were measured, and the impact of a short shock (SS) at 42°C/2hrs versus a longer treatment

(LT) at 38-35°C/24hrs on pigment synthesis, and on the expression of rubisco activase (Rca1)

coding gene were investigated. A classication system was built to describe the tolerance

to HT, and cultivars were grouped via UPGMA, and PCoA. Results show that SS impacted

pigment synthesis more than LT, while expression of Rca1 was cultivar-specic; In a group of

19 cultivars under two treatments (T1, T2) at 30°C, the vulnerable: moderately tolerant: tolerant

were 4: 11: 5, and 3:9:7, respectively. Values were cultivar-specic for single parameters, yet a

general trend was evident for some. Improved tolerance to repeated stress was described as

gained stress memory.

Keywords: biochemical synthesis, gene expression, primed stress memory,

hierarchical clustering.

2

Vol.10 No.3

December, 2024

Balkan Journal of

Interdisciplinary Research

E-ISSN 2411-9725

ISSN 2410-759X

1. Introduction

Continuous increase in heat waves have contributed to a 0,5°C increase in mean

global temperature (Mishra et al, 2021), which have a severe impact on crops growth,

yield and product quality as revealed by mathematical modelling (Semenov and

Shewry, 2011; Mishra et al, 2021; Zhao et al, 2022). However, the way wheat responds

to HT could be varied due to dierence in thermotolerance nature of cultivars

(Mishra et al, 2018; Mishra et al, 2021). In general, plants do survive and grow in HT

thanks to mechanisms classied as: Avoidance and Tolerance (Mishra et al, 2021), or

as Avoidance, Escape and Tolerance (Poudel and Poudel, 2020). The rst includes

various morphological adaptations, expression of genes encoding proteins or

accumulation of stress-associated proteins, while the tolerance as described by Mishra

et al (2021) involves alterations in expression of genes encoding ion transporters,

transcription factors or enzymes involved in osmoprotectants, and antioxidant

molecule biosynthesis. The same concept described by Poudel (2020) involves the

antioxidant defense, generation of Heat Shock Proteins (HSPs), and Stay Green (SG),

with the last (SG) concept associated to genotypes maintenance of photosynthesis

and grain lling in HS condition through late expression of senescence related genes.

It is clear that understanding the wheat responses to HT is a challenge, while the

role of multiomics approaches for this purpose, has not been well documented

(Mishra et al, 2021). Wheat productivity is reported to be reduced remarkably due

to harmful eect of HT in growth process (Poudel et al, 2020). Thus, the pre-anthesis

HT is reported to retard physiological processes such as the pollen viability, seed

formation, embryo development (Khan et al, 2020), reduces the crop total duration

by causing early owering and shortening the grain lling period (Mohan et al, 2017;

Lamaoni, 2018; Pandey et al, 2022), deactivates the Rubisco enzyme and rubisco

activase (Poudel et al, 2020), inhibits the chlorophyll uorescence and mitochondrial

respiration (Iqbal, 2017), reduces the rate of assimilate translocation, and causes a

premature leaf senescence (Poudel et al, 2020). Considering the morphological

features, the leaf appearance rate, leaf elongation rates, leaf-elongation duration

(Liu et al, 2011), number of leaves (Sharma, 2015), root growth (Chauhan et al, 2011),

number of roots, root length and root diameter (Iqbal, 2017) are among the well

documented characteristics impacted by HT, along with biochemical processes such

as the oxidative stress, during which plants highly produce ROS, which interrupt

the cell function by their negative actions on lipid, protein and DNA. In this overall

context of physiological, biochemical, morphological and agronomical characteristics

impacted by HT, the building of thermo-tolerance strategies becomes a necessity for

the sustainability of crop yield (Khan et al, 2021). It is already reported that plants

can acquire heat stress tolerance (HST) through priming, which establishes stress

memory during mild or severe transient heat stress (Wang et al, 2014; Serrano et al,

2019). The impact of heat priming during early vegetative stages (before anthesis)

(Wang et al, 2014; Khanzada et al, 2021; Wang et al, 2016), during the stem-elongation

stage, booting and anthesis (Fan et al, 2018) on the post-anthesis phases resulted in