Evolution of resistance in weeds to herbicides is threatening world agricultural production. Weed management has become more complicated with the development of non-target site resistance (NTSR) to herbicides in weeds. The NTSR mechanisms can be caused by herbicide metabolism, altered patterns of translocation, and herbicide absorption/penetration. Metabolism of herbicides consists of an activation phase and then a conjugation phase, though in some cases no activation phase is needed. The activation phase mainly involves the addition of functional groups to herbicide molecules using enzymes such as cytochrome P-450. Transcriptome-wide gene expression has shown that genes which encode for several cytochrome P-450s are upregulated in weeds resistant to ACCase-inhibitor and ALS-inhibitor herbicides. In the conjugated phase, several studies have shown that two important types of enzyme, glutathione S-transferases and glucosyltransferases, play crucial roles in conferring resistance to herbicides. An altered pattern of translocation can also play a crucial role in conferring NTSR to weeds. With glyphosate and paraquat, it has been shown that altered patterns of translocation are due to sequestration of the herbicide into vacuoles. However, some other little known mechanisms such as “hyper-sensitive” reactions, impaired translocation, and root exudation can affect the patterns of herbicide translocation within resistant weeds. The molecular understanding of NTSR mechanisms is still in its infancy. Recent developments in techniques such as high-throughput DNA/RNA sequencing technologies will soon allow further insights into the NTSR mechanisms in weeds. This information is essential for developing strategies to overcome weeds with the NTSR mechanisms.

Abiotic and biotic stresses pose significant challenges to global agricultural productivity. Plants have developed complex regulatory mechanisms to mitigate these stresses, involving signaling networks that mediate physiological, biochemical, and molecular responses. Among these mechanisms, protein phosphorylation plays a crucial role in plant stress adaptation, with protein phosphatase 2C (PP2C) proteins acting as key regulators in various signaling pathways. PP2Cs modulate plant stress responses through interactions with a range of proteins, including SnRK2 kinases, ABA receptors, transcription factors, and ion channels, allowing them to fine-tune signaling pathways and physiological responses under stress conditions. This review provides a comprehensive analysis of the PP2C gene family in plants, focusing on their characteristics, regulatory mechanisms, and functional roles in abiotic and biotic stress responses. We highlight the biological significance of PP2Cs, and their involvement in modulating key pathways, including abscisic acid (ABA), MAP kinase (MAPK), and calcium signaling. Furthermore, we discuss the role of PP2Cs in controlling root development, stomatal regulation, ion homeostasis, and immune responses, highlighting their roles in coordinating plant developmental programs with adaptive mechanisms activated during stress conditions, particularly under limited resources. We also identified key research gaps and outlined future directions that could enhance our understanding of PP2Cs' regulatory roles in physiological processes, stress responses, and developmental signaling pathways. Gaining deeper insights into PP2C-mediated functions may open new opportunities for advancing agricultural sustainability.

In New Zealand, pastoral farming for dairy and meat production is the major land use. As with any agricultural production system, weeds are a threat to efficient pasture production in New Zealand. In this review, we outline the problems caused by weeds in New Zealand pastures, and the management strategies being used to control them. There are currently 245 plant species from 40 plant families that are considered to be troublesome weeds in New Zealand pastures. The application of herbicides is an important approach to manage weeds in New Zealand pastures; however, a key to the success of these pastures is the use of clovers in combination with the grasses, so the challenge is to find herbicides that selectively control weeds without damaging these legumes. The use of spot spraying and weed wiping are often required to ensure selective control of some weed species in these pastures. Non-chemical agronomic approaches such as grazing management and using competitive pasture species often play a more important role than herbicides for weed management in many New Zealand pastures. Thus, integrated weed management using a combination of herbicides and good pasture management strategies leads to the most cost-effective and efficient control of pasture weeds in New Zealand.