Effects of chitin and chitosan on root growth, biochemical defense response and exudate proteome ofCannabis sativa

Abstract

Fungal pathogens pose a major threat toCannabis sativaproduction, requiring safe and effective management procedures to control disease. Chitin and chitosan are natural molecules that elicit plant defense responses. Investigation of their effects onC. sativawill advance understanding of plant responses towards elicitors and provide a potential pathway to enhance plant resistance against diseases. Plants were grown in thein vitroRoot-TRAPR system and treated with colloidal chitin and chitosan. Plant morphology was monitored, then plant tissues and exudates were collected for enzymatic activity assays, phytohormone quantification, qPCR analysis and proteomics profiling. Chitosan treatments showed increased total chitinase activity and expression of pathogenesis-related (PR) genes by 3-5 times in the root tissues. In the exudates, total peroxidase and chitinase activities and levels of defense proteins such as PR protein 1 and endochitinase 2 were increased. Shoot development was unaffected, but root development was inhibited after chitosan exposure. No significant effects on plant defense were observed upon chitin treatment. These results indicate that colloidal chitosan significantly promoted production and secretion of plant defense proteins inC. sativaroot system and could be used as a potential elicitor, particularly in hydroponic scenarios to manage crop diseases.

Hormonal and proteomic analyses of southern blight disease caused by Athelia rolfsii and root chitosan priming on Cannabis sativa in an in vitro hydroponic system

“…Nevertheless, chitosan treatment has a root‐growth inhibitory effect, where root length and surface area of chitosan‐treated plants were significantly smaller than those of the untreated plants (Figures 2 and 3a,b). These findings confirm the chitosan effects on C. sativa root systems in buttressing plant defense but forfeiting root expansion (Suwanchaikasem et al, 2023). The similar outcome of chitosan inhibiting root growth but promoting plant defense was also found in Arabidopsis studies (Iglesias et al, 2019; Lopez‐Moya et al, 2017).…”

“…In the list of C. sativa significant proteins, many are plant defense proteins, for example, pathogenesis‐related (PR) protein R major‐form like (CS_02), thaumatin‐like protein 1 (CS_06), peroxidase 57‐like (CS_13), and peroxidase 24 (CS_16). Their intensities were significantly increased in chitosan treatment or chitosan + A. rolfsii condition (Figure 9b and Table 1), confirming the eliciting effect of chitosan to induce C. sativa roots to secrete defense proteins into exudate (Suwanchaikasem et al, 2023). For A. rolfsii proteins, their functions were tentatively assigned based on BLAST results, where the full protein sequence was aligned against the NCBI fungal protein repository and the first‐hit protein with the highest alignment score and annotated protein name was selected (Tables 1 and S1).…”

“…The analysis was performed using the Triple‐Quad 6410 LC–MS machine (Agilent Technologies, USA) equipped with Poroshell 120 EC‐C18 column (2.7 μm; 2.1 × 100 mm, Agilent Technologies, USA). The LC and MS parameters were set as described previously (Suwanchaikasem et al, 2023).…”

“…After concentration using an Amicon Ultra‐15, 10 kDa MWCO centrifugal device (Merck Millipore, Germany), 100 μL of concentrated exudate proteins (approximately 5–11 μg protein) were aliquoted from each sample and processed with the S‐Trap micro spin column (Protifi, USA) using the protocol previously described (Suwanchaikasem et al, 2023). Final peptides were loaded into the nano‐LC–MS/MS system.…”

“…The eliciting effect of chitosan on the C. sativa root defense systems was recently reported. These results showed that .2% to .5% colloidal chitosan can induce production and secretion of defense proteins in root tissues and exudates (Suwanchaikasem et al, 2023). This was the impetus for further study to examine whether chitosan‐primed plants will be more resistant against fungal diseases.…”