The APETALA2/Ethylene-Responsive Transcriptional Factors containing conservative AP2/ERF domains constituted a plant-specific transcription factor (TF) superfamily, called AP2/ERF. The configuration of the AP2/ERF superfamily in maize has remained unresolved. In this study, we identified the 229 AP2/ERF genes in the latest (B73 RefGen_v5) maize reference genome. Phylogenetic classification of the ZmAP2/ERF family members categorized it into five clades, including 27 AP2 (APETALA2), 5 RAV (Related to ABI3/VP), 89 DREB (dehydration responsive element binding), 105 ERF (ethylene responsive factors), and a soloist. The duplication events of the paralogous genes occurred from 1.724–25.855 MYA, a key route to maize evolution. Structural analysis reveals that they have more introns and few exons. The results showed that 32 ZmAP2/ERFs regulate biotic stresses, and 24 ZmAP2/ERFs are involved in responses towards abiotic stresses. Additionally, the expression analysis showed that DREB family members are involved in plant sex determination. The real-time quantitative expression profiling of ZmAP2/ERFs in the leaves of the maize inbred line B73 under ABA, JA, salt, drought, heat, and wounding stress revealed their specific expression patterns. Conclusively, this study unveiled the evolutionary pathway of ZmAP2/ERFs and its essential role in stress and developmental processes. The generated information will be useful for stress resilience maize breeding programs.

Lead (Pb) is the most common heavy metal contaminant in the environment, and its concentration is continuously increasing owing to anthropogenic activities. Phytoremediation is a green technique used globally to remediate polluted soils. The role of weeds as potential phytoremediation agents has rarely been reported in the literature. Weeds are more tolerant to abiotic stress; hence, it was hypothesized that these can serve the purpose more efficiently. Therefore, a pot experiment was conducted to evaluate the phytoremediation potential of five winter weeds, namely Avena fatua, Phalaris minor, Coronopus didymus, Chenopodium murale, and against various levels of Pb stress: control, 100 and 200 ppm. Results depicted that all the weeds could survive under higher levels of Pb; nonetheless, exposure to 200 ppm Pb stress reduced shoot dry weight (29%-69%) across all weeds. The internal CO2 concentration, photosynthesis rate, stomatal conductance, and transpiration rate decreased (5-60%) among all weeds with increasing Pb stress levels. However, Avena fatua, Phalaris minor, and Chenopodium murale depicted better gas exchange attributes than other weeds. Moreover, increased (4-60%) antioxidant activity was observed in all weeds at 100 ppm Pb level; nevertheless, it decreased at 200 ppm Pb. Additionally, Pb concentration was highest in Avena fatua, Phalaris minor, and Coronopus didymus (60-75 ppm), and the bio-accumulation factor showed that Avena fatua and Coronopus didymus were the accumulators of Pb. The translocation factor of Phalaris minor was more than 1, depicting that Pb was translocated more into shoots from roots; all other weeds accumulated more Pb in their roots than shoots. Thus, it can be concluded that different winter weeds can thrive under Pb stress, and Avena fatua and Coronopus didymus can serve the purpose of phytoremediation.