Grape root cell features related to phylloxera resistance and changes of anatomy and endogenous hormones during nodosity and tuberosity formation

Abstract

Background and Aims: Cell wall anatomical and chemical components of different phylloxera resistant grapevine roots were examined. Changes in anatomy and endogenous hormone levels were tested during phylloxera‐induced nodosity and tuberosity formation. Methods and Results: Tertiary roots of 3–5 mm diameter from 4‐year‐old grapevines with different phylloxera resistance ratings were collected in September to examine cellular anatomy and endogenous hormones in nodosities and tuberosities. Grapevine roots with reported high phylloxera resistance had more periderm cell layers, smaller parenchyma cells, and higher lignin, cellulose and pectin contents. 140 Ruggeri periderm cell wall thickened and accumulated more polyphenolic materials after phylloxera infestation. Nodosity cells distal to the insect feeding site and tuberosity cells near the feeding site showed increased cell division and enlargement. Tuberosity cells were oriented parallel to the phylloxera stylet. Endogenous hormone levels increased during nodosity formation, with zeatin and gibberellic acid continually increasing and kinetin, indole acetic acid and abscisic acid initially increasing but later decreasing. Root dehydrogenase activity was 4.85 times higher than that of uninfested controls. Conclusions: Cell features of phylloxera‐resistant Vitis species were likely physically restrictive for phylloxera feeding. Periderm cell changes of phylloxera‐resistant rootstock 140 Ruggeri infested by phylloxera prevented phylloxera infestation. Cell changes during susceptible cultivars' nodosity and tuberosity formation were beneficial for phylloxera feeding, and endogenous hormone changes during phylloxera infestation may have affected nodosity formation. Significance of the Study: A high content of cell wall chemical components could potentially be an initial, convenient assessment index in phylloxera resistance breeding. This paper revealed that endogenous hormones affected nodosity formation.

Measurement of grape root firmness and its application to the evaluation of cold hardiness

“…A previous study showed that the lignin, cellulose and pectin content varied between strains; the order was rootstocks > V. amurensis × V. vinifera > V. vinifera × V. labrusca , V. vinifera . The phylloxera‐resistance of these cultivars was consistent with the lignin, cellulose and pectin content (Wang et al , Du et al ), the anatomical structure was influenced by the chemical composition, and the greater the lignin, cellulose and pectin content the more compact the cells. Anatomical structure and chemical composition affect the rate of phylloxera stylet penetration (Du et al ), suggesting firmness of the roots may be determined by the structure and chemical composition.…”

“…The phylloxera‐resistance of these cultivars was consistent with the lignin, cellulose and pectin content (Wang et al , Du et al ), the anatomical structure was influenced by the chemical composition, and the greater the lignin, cellulose and pectin content the more compact the cells. Anatomical structure and chemical composition affect the rate of phylloxera stylet penetration (Du et al ), suggesting firmness of the roots may be determined by the structure and chemical composition. The anatomical structure and chemical composition of roots was significantly correlated with cold hardiness (Gao et al ), and grape cultivars with thick root exodermis layers, thin phloem and a high proportion of xylem had better cold hardiness than the other cultivars.…”

“…The phloem is composed of loose, irregularly arranged parenchyma cells, while the xylem is composed of more primitive vascular cells with thick walls (Pratt ). A previous study showed that rootstocks had seven to eight periderm cell layers and smaller parenchyma cells, while V. vinifera cultivars had three to five periderm cell layers (Du et al ), affecting the firmness of the root. Many studies have shown that pectin and cellulose content play an important role in fruit softening (Koh et al , Rosli et al ).…”

“…A previous study showed that the grape rootstocks, SO4, 101‐14M and 3309C, had more periderm cell layers, smaller parenchyma cells, and higher lignin, cellulose and pectin content than V. vinifera . A greater number of periderm cell layers and smaller parenchyma cells affect the rate of phylloxera stylet penetration (Du et al ), indicating that the rootstocks had a firmness greater than that of V. vinifera . Other studies have shown that many grape rootstocks have good cold hardiness (Miller et al , Gao et al ), while V. vinifera on own roots has poor cold hardiness, suggesting a positive correlation between root cold hardiness and root firmness.…”

Expression of putative expansin genes in phylloxera (Daktulosphaira vitifoliae Fitch) induced root galls of Vitis spp.

“…Even so, earlier studies have provided some evidence of physiological changes in nodosities upon attack by this insect (e.g. Forneck et al 2001b ; Kellow et al 2004 ; Du et al 2011 ) arguing that not only genes involved in cell wall modification are affected. Thus, further enzymatic changes expressed in increased activity of peroxidase, acidic phosphatase and leucine aminopeptidase have also been shown upon phylloxera attack (Forneck et al 2002 ).…”