scholarly journals Identification of Factors Linked to Higher Water-Deficit Stress Tolerance in Amaranthus hypochondriacus Compared to Other Grain Amaranths and A. hybridus, Their Shared Ancestor

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 239 ◽  
Author(s):  
Tzitziki González-Rodríguez ◽  
Ismael Cisneros-Hernández ◽  
Jonathan Acosta Bayona ◽  
Enrique Ramírez-Chavez ◽  
Norma Martínez-Gallardo ◽  
...  

Water deficit stress (WDS)-tolerance in grain amaranths (Amaranthus hypochondriacus, A. cruentus and A. caudatus), and A. hybridus, their presumed shared ancestor, was examined. A. hypochondriacus was the most WDS-tolerant species, a trait that correlated with an enhanced osmotic adjustment (OA), a stronger expression of abscisic acid (ABA) marker genes and a more robust sugar starvation response (SSR). Superior OA was supported by higher basal hexose (Hex) levels and high Hex/sucrose (Suc) ratios in A. hypochondriacus roots, which were further increased during WDS. This coincided with increased invertase, amylase and sucrose synthase activities and a strong depletion of the starch reserves in leaves and roots. The OA was complemented by the higher accumulation of proline, raffinose, and other probable raffinose-family oligosaccharides of unknown structure in leaves and/or roots. The latter coincided with a stronger expression of Galactinol synthase 1 and Raffinose synthase in leaves. Increased SnRK1 activity and expression levels of the class II AhTPS9 and AhTPS11 trehalose phosphate synthase genes, recognized as part of the SSR network in Arabidopsis, were induced in roots of stressed A. hypochondriacus. It is concluded that these physiological modifications improved WDS in A. hypochondriacus by raising its water use efficiency.

2017 ◽  
Author(s):  
América Tzitziki González-Rodríguez ◽  
Ismael Cisneros Hernández ◽  
Norma A. Martínez-Gallardo ◽  
Erika Mellado-Mojica ◽  
Mercedes López-Pérez ◽  
...  

AbstractIn this study, water deficit stress (WDS)-tolerance in several cultivars of grain amaranth species (Amaranthus hypochondriacus[Ahypo],A. cruentus[Acru] and A.caudatus[Acau]), in addition toA. hybridus(Ahyb), an ancestral amaranth, was examined. Ahypo was the most WDS-tolerant species, whereas Acau and Ahyb were WDS-sensitive. Data revealed that the differential WDS tolerance observed was multifactorial. It involved increased proline and raffinose (Raf) in leaves and/ or roots. Higher foliar Raf coincided with inducedGalactinol synthase 1(AhGolS1) andRaffinose synthase(AhRafS) expression. Unknown compounds, possibly larger RFOs, also accumulated in leaves of WDS-tolerant amaranths, which had high Raf/ Verbascose ratios. Distinct nonstructural carbohydrate (NSC) accumulation patterns were observed in tolerant species under WDS and recovery, such as: i) high Hex/ Suc ratios in roots coupled to increased cell wall and vacuolar invertase and sucrose synthase activities; ii) a severer depletion of starch reserves; iii) lower NSC content in leaves, and iv) higher basal hexose levels in roots which further increased under WDS. WDS-marker gene expression patterns proposed a link between amaranth’s WDS tolerance and abscisic acid-dependent signaling. Results obtained also suggest thatAhTRE,AhTPS9,AhTPS11,AhGolS1 and AhRafSare reliable gene markers of WDS tolerance in amaranth.HighlightDifferential water deficit stress tolerance in grain amaranths and their ancestor,Amaranthus hybridus, is a multifactorial process involving various biochemical changes and modified expression patterns of key stress-related genes.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. A. Gomaa ◽  
Essam E. Kandil ◽  
Atef A. M. Zen El-Dein ◽  
Mamdouh E. M. Abou-Donia ◽  
Hayssam M. Ali ◽  
...  

AbstractIn Egypt, water shortage has become a key limiting factor for agriculture. Water-deficit stress causes different morphological, physiological, and biochemical impacts on plants. Two field experiments were carried out at Etay El-Baroud Station, El-Beheira Governorate, Agriculture Research Center (ARC), Egypt, to evaluate the effect of potassium silicate (K-silicate) of maize productivity and water use efficiency (WUE). A split-plot system in the four replications was used under three irrigation intervals during the 2017 and 2018 seasons. Whereas 10, 15, and 20 days irrigation intervals were allocated in main plots, while the three foliar application treatments of K-silicate (one spray at 40 days after sowing; two sprays at 40 and 60 days; and three sprays at 40, 60, and 80 days, and a control (water spray) were distributed in the subplots. All the treatments were distributed in 4 replicates. The results indicated that irrigation every 15 days gave the highest yield in both components and quality. The highly significant of (WUE) under irrigation every 20 days. Foliar spraying of K-silicate three times resulted in the highest yield. Even under water-deficit stress, irrigation every fifteen days combined with foliar application of K-silicate three times achieved the highest values of grain yield and its components. These results show that K-silicate treatment can increase WUE and produce high grain yield requiring less irrigation.


2021 ◽  
Vol 22 (3) ◽  
pp. 1158
Author(s):  
Katy Díaz ◽  
Luis Espinoza ◽  
Rodrigo Carvajal ◽  
Evelyn Silva-Moreno ◽  
Andrés F. Olea ◽  
...  

Brassinosteroids (BRs) are plant hormones that play an essential role in plant development and have the ability to protect plants against various environmental stresses, such as low and high temperature, drought, heat, salinity, heavy metal toxicity, and pesticides. Mitigation of stress effects are produced through independent mechanisms or by interaction with other important phytohormones. However, there are few studies in which this property has been reported for BRs analogs. Thus, in this work, the enhancement of drought stress tolerance of A. thaliana was assessed for a series of 2-deoxybrassinosteroid analogs. In addition, the growth-promoting activity in the Rice Lamina Inclination Test (RLIT) was also evaluated. The results show that analog 1 exhibits similar growth activity as brassinolide (BL; used as positive control) in the RLIT bioassay. Interestingly, both compounds increase their activities by a factor of 1.2–1.5 when they are incorporated to polymer micelles formed by Pluronic F-127. On the other hand, tolerance to water deficit stress of Arabidopsis thaliana seedlings was evaluated by determining survival rate and dry weight of seedlings after the recovery period. In both cases, the effect of analog 1 is higher than that exhibited by BL. Additionally, the expression of a subset of drought stress marker genes was evaluated in presence and absence of exogenous applied BRs. Results obtained by qRT-PCR analysis, indicate that transcriptional changes of AtDREBD2A and AtNCED3 genes were more significant in A. thaliana treated with analog 1 in homogeneous solution than in that treated with BL. These changes suggest the activation of alternative pathway in response to water stress deficit. Thus, exogenous application of BRs synthetic analogs could be a potential tool for improvement of crop production under stress conditions.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Christina C. Vinson ◽  
Ana P. Z. Mota ◽  
Brenda N. Porto ◽  
Thais N. Oliveira ◽  
Iracyara Sampaio ◽  
...  

Abstract Raffinose family oligosaccharides (RFOs) are implicated in plant regulatory mechanisms of abiotic stresses tolerance and, despite their antinutritional proprieties in grain legumes, little information is available about the enzymes involved in RFO metabolism in Fabaceae species. In the present study, the systematic survey of legume proteins belonging to five key enzymes involved in the metabolism of RFOs (galactinol synthase, raffinose synthase, stachyose synthase, alpha-galactosidase, and beta-fructofuranosidase) identified 28 coding-genes in Arachis duranensis and 31 in A. ipaënsis. Their phylogenetic relationships, gene structures, protein domains, and chromosome distribution patterns were also determined. Based on the expression profiling of these genes under water deficit treatments, a galactinol synthase candidate gene (AdGolS3) was identified in A. duranensis. Transgenic Arabidopsis plants overexpressing AdGolS3 exhibited increased levels of raffinose and reduced stress symptoms under drought, osmotic, and salt stresses. Metabolite and expression profiling suggested that AdGolS3 overexpression was associated with fewer metabolic perturbations under drought stress, together with better protection against oxidative damage. Overall, this study enabled the identification of a promising GolS candidate gene for metabolic engineering of sugars to improve abiotic stress tolerance in crops, whilst also contributing to the understanding of RFO metabolism in legume species.


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