Resumo em Inglês:

Abstract Root-knot nematodes (Meloidogyne incognita) severely limit cotton (Gossypium spp.) productivity, with conventional control methods facing ecological and efficacy challenges. Here, we evaluate a fungal peptidogalactomann (pGM), derived from Cladosporium herbarum (commercially formulated as Hariman), as a novel biocontrol agent that primes plant defenses against nematode infection. Under greenhouse conditions, foliar application of pGM at 100 μg·mL⁻¹ resulted in an 83% reduction gall formation compared to untreated controls and yielded a four-fold increase in resistant plants (gall index = 1.5 vs. 3.2 in controls; *p* < 0.01). Nematode egg production was reduced by 60% at 120 days post-inoculation. pGM triggered a biphasic defense response, evidenced by a remarkable 40,000-fold upregulation of the systemic acquired resistance gene PR1 and transient activation of phenylpropanoid (PAL) and jasmonate (LOX2) pathways. Notably, pGM supported healthy plant growth without phytotoxicity, contrasting with the phytotoxicity often associated with chemical nematicides. These findings indicate that pGM has strong potential as a sustainable alternative for M. incognita management in cotton, primarily by enhancing host immunity rather than exerting direct nematode toxicity. Further field trials are necessary to validate its effectiveness and to evaluate its integration into integrated pest management strategies.

Resumo em Inglês:

Abstract Recurrent drought episodes, increasingly intensified by climate change, pose a growing threat to global food security by severely limiting crop productivity. Major latex-like proteins (MLPs) play crucial roles in drought tolerance, acting as regulators of stress responses. However, their involvement in adaptation to recurrent drought stress remains poorly understood. In this study, we investigated the transcriptional dynamics of MLP genes during repeated dehydration and rehydration cycles in Arachis duranensis, a tropical wild species highly resilient to drought. In silico expression profiling of 36 A. duranensis MLP genes revealed their broad involvement in recurrent drought responses, with most patterns consistent with the ‘revised-response’ category of dehydration memory genes. qRT-PCR analysis further confirmed the activation of the abscisic acid (ABA) signaling pathway during recurrent drought in A. duranensis. Functional characterization of the candidate memory gene AdMLP11 in transgenic tobacco showed that its overexpression enhances tolerance to moderate and severe recurrent drought, likely through its role as a positive regulator of phytohormone-mediated defense pathways. These findings provide novel insights into the role of MLPs in transcriptional memory and drought adaptation in wild Arachis, highlighting AdMLP11 as a promising target for biotechnological strategies to develop climate-resilient crops.