Plant lectins, a distinctive category of proteins that possess specific recognition and binding capabilities towards carbohydrates, have been studied over 130 years since the initial discovery of the lectin protein “ricin” [1]. These proteins have been comprehensively characterized and classified based on their subcellular localization, molecular structure, sequence and abundance. Subsequently, extensive investigations have been conducted to elucidate their biological functions, including plant defense mechanisms, innate immunity, signal transduction [1,2]. These ongoing researches have greatly advanced our understanding of the multifaceted roles played by plant lectins in diverse biological contexts.

Among the myriad lectin proteins, jacalin-related lectins (JALs), an extended protein family derived from jacalin, have gained significant attention and undergone comprehensive characterization. Genome wide investigation reveals there are 48 JAL genes in Arabidopsis [3]. Additionally, based on their distinctive carbohydrate-binding abilities, these JALs are further classified into two groups: the galactose-specific JALs and the mannose-specific JALs. Interestingly, the galactose-specific JALs are predominantly localized in the storage vacuoles, while the mannose-specific JALs are primarily found in the cytoplasm. Such differential subcellular localization highlights the diverse functional roles performed by these JALs within distinct intracellular compartments [4]. Subsequent functional investigations have revealed the involvement of several JALs in the plant defense process associated with endoplasmic reticulum (ER) bodies, the derived organelle from ER. ER bodies are induced in response to various stimuli including physical injury, infection by Pseudomonas syringae, and the application of exogenous methyl jasmonate (MeJA). Remarkably, two key components, namely NAI1 and NAI2, have been reported as crucial factors in the formation of ER bodies. NAI1, a putative basic-helix-loop-helix-type (bHLH) transcription factor, is found to be pivotal in orchestrating this process, while NAI2 is regulated by NAI1 and serves as an integral component of the ER body structure [[5], [6], [7], [8]]. The expression level of certain JALs (JAL22, JAL23, JAL30, JAL31 and JAL33) and PYK10 were decreased in mutant nai1–1 [5]. PYK10, a member of the Glycoside Hydrolase (GH) Family 1 beta-glycosidases (BGLUs) proteins, is known to play an essential role in the formation of ER bodies in plant seedlings and roots [9,10]. When plant cells are damaged, PYK10 forms an active complex. Previous proteomics analysis revealed that several JALs (JAL30, JAL31, JAL33, JAL34 and JAL35), GDSL lipase-like proteins (GLL22) and some BGLUs (PYK10/BGLU23, BGLU21 and BGLU22) are comprised to this complex [3]. Besides, this active PYK10 complex is regulated by several JAL proteins antagonistically, that is “polymerizer-type lectin” (JAL31 and JAL23) and “inhibitor-type lectin” (JAL30 and JAL22), then, the interaction between PYK10 and JAL30 was confirmed [3,5]. However, the interaction between GLL protein and JALs or BGLUs remains unclear and requires further investigation.

Lectin proteins are usually considered to have the specific sugar binding ability, which have been developed as the effective tools to enrich glycosylated protein, such as O-GlcNAcylation. O-GlcNAcylation is a reversible post-translational modification of Thr/Ser residues of proteins, and is involved in multiple growth and developmental processes, including signal transduction, hormone responses and virus infection [11]. Through lectin weak affinity chromatography (LWAC) coupled with mass spectrometry (MS), researchers were able to enrich and identify 145 unique O-GlcNAc-modified peptides belonging to proteins associated with synaptic transmission [12]. Furthermore, Xu et al. applied the LWAC-MS method to identify 971 O-GlcNAc-modified peptides belonging to 262 proteins in Arabidopsis, providing valuable data for further functional studies on O-GlcNAcylation in plants [13]. Additionally, a novel and rapid method utilizing an O-GlcNAc affinity gel containing wheat germ agglutinin (WGA), a GlcNAc-specific lectin, has been developed for the separation of O-GlcNAcylated proteins [14]. Given that JALs, as members of the lectin protein family, are likely to possess carbohydrate binding ability, they hold promise as bio-tools for the discovery and enrichment of O-GlcNAcylated proteins. However, research in this area is currently lacking and presents an exciting opportunity for future exploration.

In this study, we initiated an investigation into the lectin function of JAL proteins by focusing on JAL30 and elucidated its biological role in Arabidopsis. Immunoprecipitation followed by mass spectrometry and label-free quantitative analysis were performed to identify new specific interacting proteins of JAL30. Totally, we identified 81 proteins from IP products, among which 44 proteins exhibited significant interaction with JAL30 protein. As a result, our comprehensive dataset substantially contributes to bridging a significant research gap in the realm of JAL lectin proteins, further advancing our understanding of their functional properties and potential implications in plant biology.