Open Access

ARTICLE

Morpho-Anatomical and Biochemical Defense Responses of Pigeon Pea Varieties to Phytophthora Blight

Kirti A. Yadav¹, Yachana Jha¹, Haiam O. Elkatry², Heba I. Mohamed^3,*, Ahmed Mahmoud Ismail⁴, Abdelrahman R. Ahmed^2,*

1 N. V. Patel College of Pure and Applied Sciences, CVM University, V.V. Nagar, Anand, 388120, Gujarat, India
2 Food and Nutrition Science Department, Agricultural Science and Food, King Faisal University, Al-Ahsa, 31982, Saudi Arabia
3 Biological and Geological Sciences Department, Faculty of Education, Ain Shams University, Cairo, 11341, Egypt
4 Department of Arid Land Agriculture, College of Agricultural and Food Sciences, King Faisal University, Al-Ahsa, 31982, Saudi Arabia

* Corresponding Authors: Heba I. Mohamed. Email: ; Abdelrahman R. Ahmed. Email:

(This article belongs to the Special Issue: Fungal and Bacterial Disease Management in Agricultural Crops Through Biological Control, Disease Resistance, and Transcriptomics Approaches)

Phyton-International Journal of Experimental Botany 2026, 95(1), 18 https://doi.org/10.32604/phyton.2026.074570

Received 14 October 2025; Accepted 22 December 2025; Issue published 30 January 2026

Abstract

Phytophthora blight is a devastating disease of pigeon pea (Cajanus cajan) that severely impacts plant growth and productivity. This study investigates the morphological, anatomical, and biochemical responses of a susceptible variety (ICPL 11260) and a resistant variety (IPAC-02) following infection by Phytophthora. Morphological analyses showed that infection caused a drastic reduction in root length, shoot length, leaf number, fresh weight, and dry weight in the susceptible ICPL 11260 variety, with reductions ranging from 0.5- to 2-fold compared to non-infected controls. Anatomical observations revealed pronounced cellular damage and mycelial invasion in infected ICPL 11260 plants by 30 days after infection, whereas infected IPAC-02 plants exhibited no fungal colonization. Biochemical analyses further demonstrated that the resistant IPAC-02 variety accumulated higher levels of total soluble sugars, proteins, phenols, and flavonoids, along with increased activities of defense-related enzymes (chitinase and β-1,3-glucanase), compared with the susceptible ICPL 11260. Under P. cajani stress, IPAC-02 maintained significantly elevated osmolyte concentrations (total sugars 153.7 mg g⁻¹ FW; proteins 25.4 mg g⁻¹ FW), secondary metabolites (phenols 51.7 mg g⁻¹ FW; flavonoids 33.1 mg g⁻¹ FW), and PR-enzyme activities (chitinase 11.4 U mg⁻¹ protein; β-1,3-glucanase 9.1 U mg⁻¹ protein). These responses support a lignification-mediated defense mechanism in IPAC-02 and highlight its potential value for breeding Phytophthora-resistant pigeon pea cultivars.

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Keywords

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