Major latex proteins(MLPs) are a type of plant-specific proteins that primarily exist in dicotyledonous and some monocotyledonous plants. They play important roles in plant growth and development, as well as in defense against biotic and abiotic stresses. This article discusses the spatial structure, biological functions, and mechanisms of action of MLPs, providing references for further understanding of MLP family members and their applications in crop improvement.

Salt severely restricts cotton (Gossypium hirsutum) growth and production. The present study was undertaken to study the effect of salt-induced hydrogen peroxide (H₂O₂) on antioxidant enzymes in cotton. NaCl treatment or exogenous H₂O₂ was used to investigate the relationship between H₂O₂ content and levels of antioxidant enzymes including superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase (POD), and catalase (CAT), as well as the transcriptional levels of corresponding genes. H₂O₂ content increased within 24h following 200mmol L^–1 NaCl treatment. Both NaCl-induced and exogenous H₂O₂ increased the activity of antioxidant enzymes including APX and SOD and upregulated the transcriptional levels of GhcAPX1, GhFeSOD, and GhchlCSD. These increased activities and upregulated transcriptional levels were inhibited when the salt-induced H₂O₂ was scavenged by NAC. These results indicate that salt-induced H₂O₂ as a second signaling messenger modulates APX and SOD activities by regulating the transcription levels of corresponding genes, alleviating oxidative stress, and increasing salt tolerance in cotton.