Effects of Shading and Soil Moisture on the Formation of Idioblasts containing Raphides in Petioles of Taro [Colocasia esculenta (L.) Schott.]

Tanaka, Masanobu; Nakashima, Toshiki; Mori, Kinya

doi:10.2503/jjshs.72.457

Cited by 3 publications

(5 citation statements)

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“…The density of raphides is higher in taro leaves and lower in the corm (Tanaka et al, 2003a, 2003b) and highest in young fully furled leaves and is less in the mature unfurled leaves (Sunell & Healey, 1985). Taro grown in the shade and under wet conditions has fewer raphide bundles (Tanaka et al, 2003b). However, a lower number of raphide bundles does not mean a species or tissue is less acrid.…”

Section: Introductionmentioning

confidence: 99%

“…However, a lower number of raphide bundles does not mean a species or tissue is less acrid. Idioblast density in taro is a polygenic trait with a heritability ~.5 (Tanaka et al, 2003b), though no acridity heritability data are available, in the absence of an assay.…”

Section: Introductionmentioning

confidence: 99%

“…An increase in calcium availability also increases the number of raphides in callus tissue (Franceschi & Horner, 1979). The raphides are formed soon after cell division takes place and are diluted subsequently during expansion growth (Kausch & Horner, 1983;Tanaka et al, 2003aTanaka et al, , 2003b. The raphides in all species are clumped together and surrounded by a mucilaginous sheath in the idioblast.…”

Section: Introductionmentioning

confidence: 99%

“…The calcium oxalate content in taro is genetically controlled, and large variation exists across taro varieties (Lewu et al, 2009; TANSAO, 2002). The density of raphides is higher in taro leaves and lower in the corm (Tanaka et al, 2003a, 2003b) and highest in young fully furled leaves and is less in the mature unfurled leaves (Sunell & Healey, 1985). Taro grown in the shade and under wet conditions has fewer raphide bundles (Tanaka et al, 2003b).…”

Section: Introductionmentioning

confidence: 99%

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Taro raphide‐associated proteins: Allergens and crystal growth

et al. 2022

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Calcium oxalate raphide crystals are found in bundles in intravacuolar membrane chambers of specialized idioblasts cells of most plant families. Aroid raphides are proposed to cause acridity in crops such as taro (Colocasia esculenta (L.) Schott). Acridity is irritation that causes itchiness and pain when raw/insufficiently cooked tissues are eaten. Since raphides do not always cause acridity and since acridity can be inactivated by cooking and/or protease treatment, it is possible that a toxin or allergen-like compound is associated with the crystals. Using two-dimensional (2D) gel electrophoresis and mass spectrometry (MS) peptide sequencing of selected peptides from purified raphides and taro apex transcriptome sequencing, we showed the presence on the raphides of peptides normally associated with mitochrondria (ATP synthase), chloroplasts (chaperonin $60 kDa), cytoplasm (actin, profilin), and vacuole (V-type ATPase) that indicates a multistage biocrystallation process ending with possible invagination of the tonoplast and addition of mucilage that may be derived from the Golgi. Actin might play a crucial role in the generation of the needle-like raphides.One of the five raphide profilins genes was highly expressed in the apex and had a 17-amino acid insert that significantly increased that profilin's antigenic epitope peak.A second profilin had a 2-amino acid insert and also had a greater B-cell epitope prediction. Taro profilins showed 83% to 92% similarity to known characterized profilins. Further, commercial allergen test strips for hazelnuts, where profilin is a secondary allergen, have potential for screening in a taro germplasm to reduce acridity and during food processing to avoid overcooking. HighlightsAll edible Aroids cause allergic type responses (acridity) thought to be caused by the sharp calcium oxalate raphide crystals. We have shown that raphide-associated proteins could guide biomineralization, and the profilins found are potential allergens.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Taro raphide‐associated proteins: Allergens and crystal growth

et al. 2022

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“…Previous investigations suggested that ascorbic acid is a precursor to oxalic acid biosynthesis (Keates et al, 2000;Kostman et al, 2001). Exogenous application of calcium, shading, and soil moisture content directly regulate the level of CaOx in 'taro' organs (Islam et al, 2015;Tanaka et al, 2003c). Unfortunately, there is little data available on the potentially edible candidate species Colocasia esculenta var.…”

Section: Introductionmentioning

confidence: 99%

Physiological, Organic and Inorganic Biochemical Changes in the Leaves of Elephant Ear (<i>Colocasia esculenta</i> Schott var. aquatillis)

et al. 2019

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Plants produce a variety of crystals with different shapes and sizes. Based on their appearance, calcium oxalate crystals, especially raphides, have been suggested to play a key role in the defense mechanism against insect attack and microbial infections. Colocasia esculenta, a tropical plant primarily grown for its edible corms contains a large number of cells (idioblasts) with needle-like crystals of calcium oxalate (i.e., raphides). The concentration of raphides in the plant varies with the ploidy level, cultivar, organ, and micro environment. The objective of this study was to evaluate the physiological, organic and inorganic biochemical changes in the differentiated leaves of elephant ear (Colocasia esculenta var. aquatilis) and examine the rate of release of these compounds in water soluble forms. Regarding photosynthetic functions, the net photosynthetic rate (P n) was positively related to light intensity, especially in fully expanded and old leaves. However, the P n , transpiration rate (E), and stomatal conductance (g s) in young leaves were lower than those in fully expanded and older leaves, resulting in low levels of total soluble sugar content in both the petioles and leaf blades of young leaves. In contrast, oxalic acid and calcium in both petioles and leaf blades peaked at > 2.0 mg•g −1 FW and 185 mg•g −1 FW, respectively. A large number of idioblasts (~5.5 idioblasts per observed microscopic field) were observed in young leaves. Oxalic acid and calcium ions extracted from the leaf tissues were rapidly dissolved in hot water (85°C) for 10-15 min, leading to a decline in the number of idioblasts. Based on these results, petioles and leaf organs of elephant ear may be eaten safely after boiling in hot water for 15 min to dissolve CaOx.

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CALCIUM OXALATE IN PLANTS: Formation and Function

Franceschi

Nakata

2005

Annu. Rev. Plant Biol.

1,032

846

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Calcium oxalate (CaOx) crystals are distributed among all taxonomic levels of photosynthetic organisms from small algae to angiosperms and giant gymnosperms. Accumulation of crystals by these organisms can be substantial. Major functions of CaOx crystal formation in plants include high-capacity calcium (Ca) regulation and protection against herbivory. Ultrastructural and developmental analyses have demonstrated that this biomineralization process is not a simple random physical-chemical precipitation of endogenously synthesized oxalic acid and environmentally derived Ca. Instead, crystals are formed in specific shapes and sizes. Genetic regulation of CaOx formation is indicated by constancy of crystal morphology within species, cell specialization, and the remarkable coordination of crystal growth and cell expansion. Using a variety of approaches, researchers have begun to unravel the exquisite control mechanisms exerted by cells specialized for CaOx formation that include the machinery for uptake and accumulation of Ca, oxalic acid biosynthetic pathways, and regulation of crystal growth.

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Effects of Shading and Soil Moisture on the Formation of Idioblasts containing Raphides in Petioles of Taro [Colocasia esculenta (L.) Schott.]

Cited by 3 publications

References 5 publications

Taro raphide‐associated proteins: Allergens and crystal growth

Taro raphide‐associated proteins: Allergens and crystal growth

Physiological, Organic and Inorganic Biochemical Changes in the Leaves of Elephant Ear (<i>Colocasia esculenta</i> Schott var. aquatillis)

CALCIUM OXALATE IN PLANTS: Formation and Function

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