Unravelling distinct proteome changes in two maize inbreds with contrasting stalk-lodging resistance upon drought

Stalk-lodging and drought are major constraints limiting maize productivity. We previously characterized B73 as stalk-lodging resistant but drought-sensitive maize inbred, while EA2024 is stalk-lodging susceptible and drought-tolerant. Using these inbreds, we performed a comparative proteomic analysis under well-watered and drought conditions. Our results revealed that drought induces extensive proteomic reprogramming in B73, while the EA2024 proteome remains unaltered. Comparative analyses identified 481 differentially accumulated proteins between inbreds across conditions. Among them, 100 proteins were differentially accumulated in well-watered conditions but showed no significant (or attenuated) differences upon drought. We defined these B73 proteins as having a convergent response to drought. Their functional characterization revealed that one third relates to upstream elements of the photosynthetic machinery, suggesting that B73 reprograms its energetic machinery to achieve an organization similar to EA2024. We also identified 381 proteins differentially accumulated between inbreds upon drought, defined as having a divergent response to drought. In this case, B73 over-accumulates proteins mainly involved in cofactors, vitamins metabolism and signaling and under-accumulates proteins linked to downstream photosynthetic components and biosynthetic processes. Thus, the convergent response suggests a partial shift of drought sensitive B73 toward the baseline of drought resistant EA2024. However, the broader divergent response of B73 suggests an inbred-specific metabolic reprogramming associated with reduced energy production, metabolic impairment and altered signaling cascades. Our findings open the possibility that stalk-lodging resistance in B73 was acquired at the expense of drought tolerance, prompting further investigation into the correlation between these two traits across a broader range of maize inbreds.