Scanning electron microscopy in nematode-induced giant transfer cells

Area of Science:

• Plant Pathology
• Cell Biology
• Nematology

Background:

• Root-knot nematodes (Meloidogyne incognita) induce specialized giant cells in host plant roots.
• Giant cells are crucial for nematode feeding and development.
• Understanding giant cell structure is key to plant-parasite interactions.

Purpose of the Study:

• To investigate the ultrastructure of giant cells induced by Meloidogyne incognita in Impatiens balsamina.
• To characterize the development and distribution of wall ingrowths in these giant cells.
• To compare giant cell wall development with normal transfer cells.

Main Methods:

• Scanning electron microscopy (SEM) was employed to examine giant cell morphology.
• KOH digestion was used to remove cytoplasmic contents and reveal inner wall structures.
• Detailed analysis of wall ingrowths and plasmodesmatal distribution.

Main Results:

• Giant cells exhibit wall ingrowths characteristic of transfer cells starting six days post-induction.
• Ingrowths develop on walls adjacent to vascular tissues, suggesting a role in nutrient transport.
• Plasmodesmatal connections are elaborated between giant cells and de novo formation occurs, while connections to surrounding cells are lost.

Conclusions:

• Giant cells induced by Meloidogyne incognita possess transfer cell-like features, enhancing their nutrient uptake capacity.
• The development of wall ingrowths and altered plasmodesmatal networks are key adaptations for nematode parasitism.
• This study provides insights into the structural modifications enabling giant cell function.