Localization of aluminium in the maize root apex: can morin detect cell wall-bound aluminium?

Eticha, Dejene; Staß, Angelika; Horst, Walter J.

doi:10.1093/jxb/eri136

Cited by 105 publications

(67 citation statements)

References 35 publications

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“…Morin can detect Al inside the cells but cannot detect cell wallbound Al. 9 This result is consistent with Al concentration in the root cell sap of overexpressed lines (Fig. 3B).…”

supporting

confidence: 87%

Further characterization of an aluminum influx transporter in rice

Xia

Yamaji²,

Feng³

2011

Plant Signaling & Behavior

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“…Morin can detect Al inside the cells but cannot detect cell wallbound Al. 9 This result is consistent with Al concentration in the root cell sap of overexpressed lines (Fig. 3B).…”

supporting

confidence: 87%

Further characterization of an aluminum influx transporter in rice

Xia

Yamaji²,

Feng³

2011

Plant Signaling & Behavior

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“…7 and 8). As morin staining was reported to be not a good index of Al bound to cell wall pectin, but it could detect Al bound to phosphate (Eticha et al, 2005), therefore our results clearly indicated that immobilization of P with Al in cell wall was involved in high Al resistance in buckwheat.…”

Section: Kochian (2002) Also Found That Hmentioning

confidence: 53%

Immobilization of Aluminum with Phosphorus in Roots Is Associated with High Aluminum Resistance in Buckwheat

et al. 2005

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Oxalic acid secretion from roots is considered to be an important mechanism for aluminum (Al) resistance in buckwheat (Fygopyrum esculentum Moench). Nonetheless, only a single Al-resistant buckwheat cultivar was used to investigate the significance of oxalic acid in detoxifying Al. In this study, we investigated two buckwheat cultivars, Jiangxi (Al resistant) and Shanxi (Al sensitive), which showed significant variation in their resistance to Al stress. In the presence of 0 to 100 mM Al, the inhibition of root elongation was greater in Shanxi than that in Jiangxi, and the Al content of root apices (0-10 mm) was much lower in Jiangxi. However, the dependence of oxalic acid secretion on external Al concentration and the time course for secretion were similar in both cultivars. Furthermore, the variation in Al-induced oxalic acid efflux along the root was similar, showing a 10-fold greater efflux from the apical 0-to 5-mm region than from the 5-to 10-mm region. These results suggest that both Shanxi and Jiangxi possess an equal capacity for Al-dependent oxalic acid secretion. Another two potential Al resistance mechanisms, i.e. Al-induced alkalinization of rhizosphere pH and root inorganic phosphate release, were also not involved in their differential Al resistance. However, after longer treatments in Al (10 d), the concentrations of phosphorus and Al in the roots of the Al-resistant cultivar Jiangxi were significantly higher than those in Shanxi. Furthermore, more Al was localized in the cell walls of the resistant cultivar. All these results suggest that while Al-dependent oxalic acid secretion might contribute to the overall high resistance to Al stress of buckwheat, this response cannot explain the variation in tolerance between these two cultivars. We present evidence suggesting the greater Al resistance in buckwheat is further related to the immobilization and detoxification of Al by phosphorus in the root tissues.Ionic aluminum (Al) is highly toxic to plant growth and appears to interfere with a number of physiological and biochemical processes (Rengel, 1992;Kochian, 1995). However, species vary widely in their ability to resist the harmful effect of Al, and significant differences in Al resistance have even been reported between genotypes of the same species (Yang et al., 2005). Over the past few decades, concerted efforts have been made to understand the genetic and physiological basis of Al resistance in many different species. As proposed by Taylor (1991), Al resistance mechanisms can be grouped into two categories. One is based on excluding Al from the root cells, and the other relies on improving the resistance of plants to the Al ions once they enter the cytosol. Among the likely exclusion mechanisms, a role for organic acid efflux has been well documented in several species (Ma, 2000;Ryan et al., 2001;Kochian et al., 2004). Other potential exclusion mechanisms include increases in rhizospheric pH (Degenhardt et al., 1998), phosphate efflux (Pellet et al., 1996), the secretion of proteins to bind Al ...

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“…Morin can detect aluminum in the cytosol but not cell wall-bound aluminum or vacuole-compartmentalized aluminum (Eticha et al, 2005b;Huang et al, 2012). The lack of morin staining in vacuole may be attributed to two reasons according to Huang et al (2012): (1) morin is not permeable to the tonoplast, and (2) vacuolar aluminum is chelated by organic reagents, such as malic and citric acids, and morin cannot detect complexed aluminum forms, similar to cell wall-bound aluminum (Eticha et al, 2005b). Therefore, strong aluminumdependent green fluorescence represents aluminum present in the cytosol and nucleus.…”

Section: Resultsmentioning

confidence: 98%

Coordination between Apoplastic and Symplastic Detoxification Confers Plant Aluminum Resistance

et al. 2013

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Whether aluminum toxicity is an apoplastic or symplastic phenomenon is still a matter of debate. Here, we found that three auxin overproducing mutants, yucca, the recessive mutant superroot2, and superroot1 had increased aluminum sensitivity, while a transfer DNA insertion mutant, xyloglucan endotransglucosylase/hydrolases15 (xth15), showed enhanced aluminum resistance, accompanied by low endogenous indole-3-acetic acid levels, implying that auxin may be involved in plant responses to aluminum stress. We used yucca and xth15 mutants for further study. The two mutants accumulated similar total aluminum in roots and had significantly reduced cell wall aluminum and increased symplastic aluminum content relative to the wild-type ecotype Columbia, indicating that altered aluminum levels in the symplast or cell wall cannot fully explain the differential aluminum resistance of these two mutants. The expression of Al sensitive1 (ALS1), a gene that functions in aluminum redistribution between the cytoplasm and vacuole and contributes to symplastic aluminum detoxification, was less abundant in yucca and more abundant in xth15 than the wild type, consistent with possible ALS1 function conferring altered aluminum sensitivity in the two mutants. Consistent with the idea that xth15 can tolerate more symplastic aluminum because of possible ALS1 targeting to the vacuole, morin staining of yucca root tip sections showed more aluminum accumulation in the cytosol than in the wild type, and xth15 showed reduced morin staining of cytosolic aluminum, even though yucca and xth15 had similar overall symplastic aluminum content. Exogenous application of an active auxin analog, naphthylacetic acid, to the wild type mimicked the aluminum sensitivity and distribution phenotypes of yucca, verifying that auxin may regulate aluminum distribution in cells.Together, these data demonstrate that auxin negatively regulates aluminum tolerance through altering ALS1 expression and aluminum distribution within plant cells, and plants must coordinate exclusion and internal detoxification to reduce aluminum toxicity effectively.

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Localization of aluminium in the maize root apex: can morin detect cell wall-bound aluminium?

Cited by 105 publications

References 35 publications

Further characterization of an aluminum influx transporter in rice

Further characterization of an aluminum influx transporter in rice

Immobilization of Aluminum with Phosphorus in Roots Is Associated with High Aluminum Resistance in Buckwheat

Coordination between Apoplastic and Symplastic Detoxification Confers Plant Aluminum Resistance

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