Utility of root cortical aerenchyma under water limited conditions in tropical maize (Zea mays L.)

Chimungu, Joseph G.; Maliro, Moses F. A.; Nalivata, Patson C.; Kanyama-Phiri, G.; Brown, Kathleen M.; Lynch, Jonathan P.

doi:10.1016/j.fcr.2014.10.009

Cited by 90 publications

(89 citation statements)

References 45 publications

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“…These results support growing evidence that root phenes and phene states that reduce the metabolic cost of soil exploration are adaptive in resource-poor soil environments (Chimungu et al, 2014a(Chimungu et al, , 2014b(Chimungu et al, , 2015Saengwilai et al, 2014;Lynch, 2015;Miguel et al, 2015;Schneider et al, 2017). In this context, root anatomical phenes merit attention as breeding targets for more stress-tolerant crops.…”

Section: Discussionsupporting

confidence: 81%

Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition

2017

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We tested the hypothesis that reduced root secondary growth of dicotyledonous species improves phosphorus acquisition. Functional-structural modeling in SimRoot indicates that, in common bean (Phaseolus vulgaris), reduced root secondary growth reduces root metabolic costs, increases root length, improves phosphorus capture, and increases shoot biomass in lowphosphorus soil. Observations from the field and greenhouse confirm that, under phosphorus stress, resource allocation is shifted from secondary to primary root growth, genetic variation exists for this response, and reduced secondary growth improves phosphorus capture from low-phosphorus soil. Under low phosphorus in greenhouse mesocosms, genotypes with reduced secondary growth had 39% smaller root cross-sectional area, 60% less root respiration, 27% greater root length, 78% greater shoot phosphorus content, and 68% greater shoot mass than genotypes with advanced secondary growth. In the field under low phosphorus, these genotypes had 43% smaller root cross-sectional area, 32% greater root length, 58% greater shoot phosphorus content, and 80% greater shoot mass than genotypes with advanced secondary growth. Secondary growth eliminated arbuscular mycorrhizal associations as cortical tissue was destroyed. These results support the hypothesis that reduced root secondary growth is an adaptive response to low phosphorus availability and merits investigation as a potential breeding target.

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Section: Discussionsupporting

confidence: 81%

Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition

2017

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“…Both RCS and RCA improve nutrient acquisition, driven by reduced root metabolic costs, and increase plant growth in edaphic stress (Zhu et al 2010;Postma and Lynch 2011a;Postma and Lynch 2011b;Schneider et al 2017b). However, reductions in nutrient and water transport and root respiration associated with RCS are significantly greater compared to RCA formation (Fan et al 2007;Zhu et al 2010;Postma and Lynch 2011b;Jaramillo et al 2013;Hu et al 2014;Saengwilai et al 2014;Chimungu et al 2015;Schneider et al 2017a).…”

Section: Rcs and Nutrient Remobilizationmentioning

confidence: 99%

“…Both RCS and RCA are accelerated by nutrient deficiencies (Gillespie and Deacon 1988;Drew et al 1989;Elliott et al 1993), reduce radial nutrient transport (Hu et al 2014;Schneider et al 2017a), reduce radial hydraulic conductivity (Fan et al 2007;Schneider et al 2017a), reduce metabolic costs (Zhu et al 2010;Postma and Lynch 2011b;Jaramillo et al 2013;Saengwilai et al 2014;Chimungu et al 2015), are influenced by exposure to ethylene (Lascaris and Deacon 1991b;Lenochová et al 2009;Schneider et al 2017c), and are types of PCD Jiang et al 2010;Schneider et al 2017c). Two ethylene-related genes were upregulated during both RCS and RCA formation (Rajhi et al 2011;Schneider et al 2017c).…”

Section: Rcs and Nutrient Remobilizationmentioning

confidence: 99%

“…Cortical phene states that reduce living cortical tissue reduce root respiration and nutrient content, thereby permitting greater resource allocation to other plant functions including growth and reproduction Lynch 2015). For example, the development of root cortical aerenchyma (RCA) in maize improves plant performance in environments with suboptimal nutrient and water availability (Zhu et al 2010;Postma and Lynch 2011a, b;Jaramillo et al 2013;Saengwilai et al 2014;Chimungu et al 2015), an effect which modeling studies show can be attributed to a reduction in root metabolic costs (Postma et al 2014;Dathe et al 2016). Fewer cell files or greater cell size in the root cortex of maize substantially reduces root respiration and improves soil exploration and water acquisition in conditions of suboptimal water availability (Chimungu et al 2014a(Chimungu et al , 2014b.…”

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confidence: 99%

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Functional implications of root cortical senescence for soil resource capture

Schneider

Lynch

2017

Plant Soil

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Background Root phenes play a primary role in plant adaptation to edaphic stress. Understanding the functional implications of root phenotypes will enable the development of crop varieties with improved soil resource acquisition. Root cortical senescence (RCS) is a type of programmed cell death in cortical cells of several Poaceae species. Until recently there has been very little attention to the functional implications of RCS for water and nutrient capture. Scope We explore the functional implications of RCS as an adaptive trait for water and nutrient acquisition. The present review summarizes evidence from our own studies and other published work, and provides novel insights into the fitness landscape of RCS. Progress has recently been achieved in understanding the development and physiological implications of RCS. We propose that RCS is a useful trait for water and nutrient acquisition, particularly in edaphic stress conditions. Conclusions Further research is needed to understand the utility and tradeoffs of RCS in the context of specific environments, management practices, and phenotypic backgrounds. The utility of RCS for improved plant performance under edaphic stress merits investigation in the field. RCS may be a useful breeding target for improved soil resource capture in several major crop species including wheat, barley, and triticale.

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“…The metabolic costs of root tissue, including respiration and the investment of scarce resources, including nutrients, are important drivers of plant tolerance to edaphic stress (Zhu et al, 2010;Postma and Lynch, 2011a;Jaramillo et al, 2013;Saengwilai et al, 2014;Chimungu et al, 2015). Respiration is a result of physiological activities such as tissue maintenance, growth, and nutrient uptake.…”

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confidence: 99%

Root Cortical Senescence Improves Growth under Suboptimal Availability of N, P, and K

et al. 2017

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Root cortical senescence (RCS) in Triticeae reduces nutrient uptake, nutrient content, respiration, and radial hydraulic conductance of root tissue. We used the functional-structural model SimRoot to evaluate the functional implications of RCS in barley (Hordeum vulgare) under suboptimal nitrate, phosphorus, and potassium availability. The utility of RCS was evaluated using sensitivity analyses in contrasting nutrient regimes. At flowering (80 d), RCS increased simulated plant growth by up to 52%, 73%, and 41% in nitrate-, phosphorus-, and potassium-limiting conditions, respectively. Plants with RCS had reduced nutrient requirement of root tissue for optimal plant growth, reduced total cumulative cortical respiration, and increased total carbon reserves. Nutrient reallocation during RCS had a greater effect on simulated plant growth than reduced respiration or nutrient uptake. Under low nutrient availability, RCS had greater benefit in plants with fewer tillers. RCS had greater benefit in phenotypes with fewer lateral roots at low nitrate availability, but the opposite was true in low phosphorus or potassium availability. Additionally, RCS was quantified in field-grown barley in different nitrogen regimes. Field and virtual soil coring simulation results demonstrated that living cortical volume per root length (an indicator of RCS) decreased with depth in younger plants, while roots of older plants had very little living cortical volume per root length. RCS may be an adaptive trait for nutrient acquisition by reallocating nutrients from senescing tissue and secondarily by reducing root respiration. These simulated results suggest that RCS merits investigation as a breeding target for enhanced soil resource acquisition and edaphic stress tolerance.

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Utility of root cortical aerenchyma under water limited conditions in tropical maize (Zea mays L.)

Cited by 90 publications

References 45 publications

Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition

Reduction in Root Secondary Growth as a Strategy for Phosphorus Acquisition

Functional implications of root cortical senescence for soil resource capture

Root Cortical Senescence Improves Growth under Suboptimal Availability of N, P, and K

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