Spectroscopic Investigation of Tomato Seed Germination Stimulated by ITrichoderma/I spp

• Published in: Biology (Basel, Switzerland) Switzerland), 2024-05, Vol.13 (5)
• Main Authors: Vukelić, Igor, Radić, Danka, Pećinar, Ilinka, Lević, Steva, Djikanović, Daniela, Radotić, Ksenija, Panković, Dejana
• Format: Article
• Language: English
• Subjects: Germination; Investigations; Metabolites; Pectin; Seeds; Tomatoes
• ISSN: 2079-7737; 2079-7737
• DOI: 10.3390/biology13050340

Fungi of the genus Trichoderma have a number of positive effects on plants that are manifested in the stimulation of plant growth and tolerance to abiotic and biotic stress factors. Our findings provide evidence for the swift response of tomato seeds to Trichoderma spp. exposure under in vitro conditions. The response was examined after 48 h of germination, before any physical contact was established between Trichoderma spp. and tomato seeds. Spectroscopic methods were used to reveal the nature of tomato seed germination stimulation by Trichoderma. Induction of the higher synthesis of phenolic compounds through plant specific responses within seed radicles was indicated. Observed differences between treatments were predominantly based on modifications in the pectin content in the middle lamella, as well as alterations in hemicelluloses and xyloglucan within the primary cell wall. Significant alterations in the composition of tomato seed radicles treated with Trichoderma spp., characterized by changes in total protein and a concurrent reduction in pectin and/or xyloglucan levels were observed. Applied spectroscopic methods are valuable tools to investigate the stimulation of seed germination by symbiotic microorganisms. Characterized by low cost and high measurement speed, they could be used in large-scale selection of the best genotype-strain combinations for better germination. Seed germination is a complex process that can be negatively affected by numerous stresses. Trichoderma spp. are known as effective biocontrol agents as well as plant growth and germination stimulators. However, understanding of the early interactions between seeds and Trichoderma spp. remains limited. In the present paper, Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to reveal the nature of tomato seed germination as stimulated by Trichoderma. A rapid response of tomato seeds to Trichoderma spp. was observed within 48 h on Murashige and Skoog medium (MS) substrate, preceding any physical contact. Raman analysis indicated that both Trichoderma species stimulated phenolic compound synthesis by triggering plant-specific responses in seed radicles. The impact of T. harzianum and T. brevicompactum on two tomato cultivars resulted in alterations to the middle lamella pectin, cellulose, and xyloglucan in the primary cell wall. The Raman spectra indicated increased xylan content in NA with T9 treatment as well as increased hemicelluloses in GZ with T4 tr