Improving plant drought tolerance and growth under water limitation through combinatorial engineering of signalling networks

Philipp Schulz; Katrin Piepenburg; Ruth Lintermann; Marco Herde; Mark A. Schöttler; Lena K. Schmidt; Stephanie Ruf; Jörg Kudla; Tina Romeis; Ralph Bock

doi:10.1111/pbi.13441

Differential Responses of Antioxidants, Abscisic Acid, and Auxin to Deficit Irrigation in Two Perennial Ryegrass Cultivars Contrasting in Drought Tolerance

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.140.6.562 ◽

2015 ◽

Vol 140 (6) ◽

pp. 562-572 ◽

Cited By ~ 14

Author(s):

Xunzhong Zhang ◽

Erik H. Ervin ◽

Yiming Liu ◽

Guofu Hu ◽

Chao Shang ◽

...

Keyword(s):

Gene Expression ◽

Antioxidant Enzymes ◽

Abscisic Acid ◽

Drought Tolerance ◽

Water Deficit ◽

Perennial Ryegrass ◽

Deficit Irrigation ◽

Sod Activity ◽

Water Limitation ◽

Silver Dollar

Water deficit is a major limiting factor for grass culture in many regions with physiological mechanisms of tolerance not yet well understood. Antioxidant isozymes and hormones may play important roles in plant tolerance to water deficit. This study was designed to investigate antioxidant enzymes, isozymes, abscisic acid (ABA), and indole-3-acetic acid (IAA) responses to deficit irrigation in two perennial ryegrass (Lolium perenne L.) cultivars contrasting in drought tolerance. The plants were subjected to well-watered {100% container capacity, 34.4% ± 0.21% volumetric moisture content (VWC), or deficit irrigation [30% evapotranspiration (ET) replacement; 28.6% ± 0.15% to 7.5% ± 0.12% VWC]} conditions for up to 8 days and rewatering for 4 days for recovery in growth chambers. Deficit irrigation increased leaf malondialdehyde (MDA) content in both cultivars, but drought-tolerant Manhattan-5 exhibited lower levels relative to drought-sensitive Silver Dollar. Superoxide dismutase (SOD) activity declined and then increased during water-deficit treatment. ‘Manhattan-5’ had higher SOD activity and greater abundance of SOD1 isozyme than ‘Silver Dollar’ under water deficit. Deficit irrigation increased catalase (CAT) and ascorbate peroxidase (APX) activity in ‘Manhattan-5’, but not in ‘Silver Dollar’. ‘Manhattan-5’ had higher CAT, APX, and peroxidase (POD) activity than ‘Silver Dollar’ during water limitation. Deficit irrigation increased mRNA accumulation of cytosolic cupper/zinc SOD (Cyt Cu/Zn SOD), whereas gene expression of manganese SOD (Mn SOD) and peroxisome APX (pAPX) were not significantly altered in response to deficit irrigation. No differences in Cyt Cu/Zn SOD, Mn SOD, and pAPX gene expression were found between the two cultivars under deficit irrigation. Water limitation increased leaf ABA and IAA contents in both cultivars, with Silver Dollar having a higher ABA content than Manhattan-5. Change in ABA level may regulate stomatal opening and oxidative stress, which may trigger antioxidant defense responses. These results indicate that accumulation of antioxidant enzymes and ABA are associated with perennial ryegrass drought tolerance. Activity and isozyme assays of key antioxidant enzymes under soil moisture limitation can be a practical screening approach to improve perennial ryegrass drought tolerance and quality.

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Transcriptional and Metabolic Profiling of Potato Plants Expressing a Plastid-Targeted Electron Shuttle Reveal Modulation of Genes Associated to Drought Tolerance by Chloroplast Redox Poise

International Journal of Molecular Sciences ◽

10.3390/ijms21197199 ◽

2020 ◽

Vol 21 (19) ◽

pp. 7199

Author(s):

Juan J. Pierella Karlusich ◽

Rocío C. Arce ◽

Fahimeh Shahinnia ◽

Sophia Sonnewald ◽

Uwe Sonnewald ◽

...

Keyword(s):

Electron Transport ◽

Drought Tolerance ◽

Metabolic Profiling ◽

Agronomic Traits ◽

Normal Growth ◽

Photosynthetic Electron Transport ◽

Redox Status ◽

Electron Shuttle ◽

Plant Tolerance ◽

Water Limitation

Water limitation represents the main environmental constraint affecting crop yield worldwide. Photosynthesis is a primary drought target, resulting in over-reduction of the photosynthetic electron transport chain and increased production of reactive oxygen species in plastids. Manipulation of chloroplast electron distribution by introducing alternative electron transport sinks has been shown to increase plant tolerance to multiple environmental challenges including hydric stress, suggesting that a similar strategy could be used to improve drought tolerance in crops. We show herein that the expression of the cyanobacterial electron shuttle flavodoxin in potato chloroplasts protected photosynthetic activities even at a pre-symptomatic stage of drought. Transcriptional and metabolic profiling revealed an attenuated response to the adverse condition in flavodoxin-expressing plants, correlating with their increased stress tolerance. Interestingly, 5–6% of leaf-expressed genes were affected by flavodoxin in the absence of drought, representing pathways modulated by chloroplast redox status during normal growth. About 300 of these genes potentially contribute to stress acclimation as their modulation by flavodoxin proceeds in the same direction as their drought response in wild-type plants. Tuber yield losses under chronic water limitation were mitigated in flavodoxin-expressing plants, indicating that the flavoprotein has the potential to improve major agronomic traits in potato.

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