scholarly journals Uncoupling differential water usage from drought resistance in a dwarf Arabidopsis mutant

2021 ◽  
Author(s):  
Daniel N Ginzburg ◽  
Flavia Bossi ◽  
Sueng Yon Rhee

Understanding the molecular and physiological mechanisms of how plants respond to drought is paramount to breeding more drought resistant crops. Certain mutations or allelic variations result in plants with altered water-use requirements. To correctly identify genetic differences which confer a drought phenotype, plants with different genotypes must therefore be subjected to equal levels of drought stress. Many reports of advantageous mutations conferring drought resistance do not control for soil water content variations across genotypes and may therefore need to be re-examined. Here, we reassessed the drought phenotype of the Arabidopsis thaliana dwarf mutant, chiquita1-1 (also called cost1), by growing mutant seedlings together with the wild type to ensure uniform soil water availability across genotypes. Our results demonstrate that the dwarf phenotype conferred by loss of CHIQ1 function results in constitutively lower water usage, but not increased drought resistance.

2014 ◽  
Vol 34 (2) ◽  
pp. 203-210 ◽  
Author(s):  
Fernando da S. Barbosa ◽  
Rubens D. Coelho ◽  
Rafael Maschio ◽  
Carlos J. G. de S. Lima ◽  
Everaldo M. da Silva

Soil water availability is the main cause of reduced productivity, and the early development period most sensitive to water deficit. This study aimed to evaluate the drought resistance of the varieties of sugar-cane RB867515 and SP81-3250 during the early development using different levels of water deficit on four soil depths. The experiment was conducted at the Department of Biosystems at Escola Superior de Agricultura "Luiz de Queiroz" (ESALQ/USP) in a greenhouse in soil classified as Oxisol, sandy loam texture (Series "Sertãozinho"). Once exhausted the level of available water in the soil, the dry strength of the studied strains are relatively low. Water balance with values less than -13 mm cause a significant decrease in the final population of plants, regardless of the variety, and values below -35 mm, leads to the death of all plants.


1991 ◽  
Vol 71 (3) ◽  
pp. 689-694 ◽  
Author(s):  
Safaa H. Al-Hamdani ◽  
Jennifer M. Murphy ◽  
Glenn W. Todd

Stomatal conductance and CO2 assimilation were evaluated at three different levels of soil water availability as tools for estimating relative drought resistance in sorghum (Sorghum bicolor (L.) Moench) at vegetative stage (preanthesis). Four genotypes differing in drought resistance in the field (A Texas line TX 622; Oklahoma lines, BOK 11 and BOK 111; and IN-15, a line from the Sudan of Africa) were investigated. Plants were grown in a growth chamber at 27 °C, (day/night) day length of 14 h and photosynthetic photon flux density of 350 μmol m−2 S−1. Three weeks after germination, plants were divided into control, 50% and 25% soil water saturation groups. At the end of the second week of treatment, simultaneous measurements were made of stomatal conductance, CO2 assimilation, leaf water potential and transpiration, on the youngest most mature leaf. After gas exchange measurements were taken, leaf water potential was measured. In a separate experiment, survival rate under water stress conditions was also determined on plants grown under the same conditions as above. Four weeks after germination, the plants were subjected to two cycles of drought and the survival rate and growth of each genotype determined. Survival rate and growth throughout dought cycles I and II was, in the decreasing order of, IN-15, BOK 111, TX 622 and BOK 11. Water potential, stomatal conductance and CO2 assimilation of each genotype declined with decreased soil water availability; the smallest decrease was observed in IN-15 and the largest decreases in BOK 111, followed by TX 622 and BOK 11. Water use efficiency of each genotype was increased, in the same order as above, with decreased soil water availability. This correlates with the ranking obtained in the artificial drought test. In conclusion, stomatal conductance and CO2 assimilation appear to be useful tools for screening sorghum genotypes at vegetative stage (preanthesis) of growth for drought resistance. Key words: Water potential, water use efficiency (WUE), Sorghum bicolor (L.) Moench


Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 95
Author(s):  
Yuan Gong ◽  
Christina L. Staudhammer ◽  
Susanne Wiesner ◽  
Gregory Starr ◽  
Yinlong Zhang

Understanding plant phenological change is of great concern in the context of global climate change. Phenological models can aid in understanding and predicting growing season changes and can be parameterized with gross primary production (GPP) estimated using the eddy covariance (EC) technique. This study used nine years of EC-derived GPP data from three mature subtropical longleaf pine forests in the southeastern United States with differing soil water holding capacity in combination with site-specific micrometeorological data to parameterize a photosynthesis-based phenological model. We evaluated how weather conditions and prescribed fire led to variation in the ecosystem phenological processes. The results suggest that soil water availability had an effect on phenology, and greater soil water availability was associated with a longer growing season (LOS). We also observed that prescribed fire, a common forest management activity in the region, had a limited impact on phenological processes. Dormant season fire had no significant effect on phenological processes by site, but we observed differences in the start of the growing season (SOS) between fire and non-fire years. Fire delayed SOS by 10 d ± 5 d (SE), and this effect was greater with higher soil water availability, extending SOS by 18 d on average. Fire was also associated with increased sensitivity of spring phenology to radiation and air temperature. We found that interannual climate change and periodic weather anomalies (flood, short-term drought, and long-term drought), controlled annual ecosystem phenological processes more than prescribed fire. When water availability increased following short-term summer drought, the growing season was extended. With future climate change, subtropical areas of the Southeastern US are expected to experience more frequent short-term droughts, which could shorten the region’s growing season and lead to a reduction in the longleaf pine ecosystem’s carbon sequestration capacity.


Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 341-350
Author(s):  
Jean T Greenberg ◽  
F Paul Silverman ◽  
Hua Liang

Abstract Salicylic acid (SA) is required for resistance to many diseases in higher plants. SA-dependent cell death and defense-related responses have been correlated with disease resistance. The accelerated cell death 5 mutant of Arabidopsis provides additional genetic evidence that SA regulates cell death and defense-related responses. However, in acd5, these events are uncoupled from disease resistance. acd5 plants are more susceptible to Pseudomonas syringae early in development and show spontaneous SA accumulation, cell death, and defense-related markers later in development. In acd5 plants, cell death and defense-related responses are SA dependent but they do not confer disease resistance. Double mutants with acd5 and nonexpressor of PR1, in which SA signaling is partially blocked, show greatly attenuated cell death, indicating a role for NPR1 in controlling cell death. The hormone ethylene potentiates the effects of SA and is important for disease symptom development in Arabidopsis. Double mutants of acd5 and ethylene insensitive 2, in which ethylene signaling is blocked, show decreased cell death, supporting a role for ethylene in cell death control. We propose that acd5 plants mimic P. syringae-infected wild-type plants and that both SA and ethylene are normally involved in regulating cell death during some susceptible pathogen infections.


2021 ◽  
Vol 257 ◽  
pp. 107147
Author(s):  
Sai-Yong Zhu ◽  
Zheng-Guo Cheng ◽  
Tao Tian ◽  
Dong-Shan Gong ◽  
Guang-Chao Lv ◽  
...  

2021 ◽  
pp. 129716
Author(s):  
Gustavo Galo Marcheafave ◽  
Cláudia Domiciano Tormena ◽  
Amelia Elena Terrile ◽  
Carlos Alberto Rossi Salamanca-Neto ◽  
Elen Romão Sartori ◽  
...  

2011 ◽  
Vol 23 (3) ◽  
pp. 219-229 ◽  
Author(s):  
Cibele T. Costa ◽  
Mércio L. Strieder ◽  
Stephen Abel ◽  
Carla A. Delatorre

Changes in root architecture are an important adaptive strategy used by plants in response to limited nutrient availability to increase the odds of acquiring them. The quiescent center (QC) plays an important role by altering the meristem activity causing differentiation and therefore, inducing a determinate growth program. The arabidopsis mutant pdr23 presents primary short root in the presence of nitrate and is inefficient in the use of nucleic acids as a source of phosphorus. In this study the effect of the pdr23 mutation on the QC maintenance under low phosphorus (P) and/or nitrogen is evaluated. QC identity is maintained in wild-type in the absence of nitrate and/or phosphate if nucleic acids can be used as an alternative source of these nutrients, but not in pdr23. The mutant is not able to use nucleic acids efficiently for substitute Pi, determinate growth is observed, similar to wild-type in the total absence of P. In the absence of N pdr23 loses the expression of QC identity marker earlier than wild-type, indicating that not only the response to P is altered, but also to N. The data suggest that the mutation affects a gene involved either in the crosstalk between these nutrients or in a pathway shared by both nutrients limitation response. Moreover loss of QC identity is also observed in wild-type in the absence of N at longer limitation. Less drastic symptoms are observed in lateral roots of both genotypes.


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