# Phytomicrobiones: A Potential Approach for Sustainable Pesticide Biodegradation
## 3 Phytomicrobiome and Pesticide Biodegradation  
Phytomicrobiomes, encompassing various endophytic microbes that contribute to the degradation of multiple compounds, including pesticides, have emerged as a critical avenue in pesticide biodegradation processes. These microbial ecosystems permeate every part of the plant, from roots to leaves, creating a multifaceted landscape of possibilities (Figure 3). The upper portion of the phytomicrobiome constitutes the shoot, stem, leaf, seed, and flower microbiomes, collectively referred to as endo and phylomicrobiome (Figure 3), while the root microbiome establishes critical plant-microbe interactions in the lower part. Figure 3: Different parts of phytomicrobiome and its development. Plant–microbiome interaction mostly starts from root zone. Generally, root microbiome controls the microbial development of phytomicrobiome. The composition of phytomicrobiomes is far from static, shaped by the host plant species, growth stage, and the environmental conditions surrounding their growth [76]. Such distinctive properties underscore the phytomicrobiome's relevance in pesticide degradation. Nevertheless, despite their immense potential, we still possess limited knowledge about how these microbiomes assemble in various plant parts and their specific contributions to pesticide degradation. In pesticide-driven conditions, plants employ a strategic partnership with root microbes, selectively enlisting beneficial microbes to their aid [77]. They communicate through root exudates, volatile organic compounds (VOCs), and phytomicrones, facilitating the recruitment of pesticide-tolerant microbes in the root zone [78]. Figure 4 illustrates how phytomicrobiomes create niches for pesticide-degrading microbes. Phytomicrobiomes are not isolated entities but function as intricate networks within and between species, genera, and families, regulating microbial assembly inside the plant's body [79]. This interplay between plants and microbes shapes diverse microbiome assemblies that enable plants to thrive in the presence of applied pesticides or other stress conditions [80; 81]. For example, endophytic strains like _Pseudomonas_ spp. and _Bacillus_ spp. enhance their functionality under stress conditions by secreting siderophores and indole acetic acid, bolstering plant growth [82] and concurrently serving as biodegradation of pesticides like 2,4-D, endosulfan, and chlorpyrifos [41; 52; 53]. One study focusing on shoot-tip-associated bacteria from banana cv. grand name identified dominant bacterial families such as Pseudomonas, Nocardiaceae, Nocardioidaceae, and Streptomyectaceae in shoot biomass. The microbial diversity in terms of culturable endophytes included Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes phyla [83]. Stem microbiomes, on the other hand, typically feature phyla like Proteobacteria, Actinobacteria, Firmicutes, Ascomycota,  
Figure 4: Phytomicrobiome development under pesticide exposed condition and secretion of root exudates provide better niches for pesticide-degradable microbes not only in the root zone but also in other parts of the phytomicrobiome. Basidiomycota, and Bacteroidetes [84]. The application of pesticides leads to shifts in the microbial structure of the shoot and stem, opening up opportunities for exploring the pesticide biodegradation potential of these altered communities. Bacteria like _Acetobacter_ spp. from sugarcane stems [85], _Azarcus_ spp. from Kallar grass shoots [86], _Bacillus megaterium_ from maize stems [87], _Burkholderia_ spp. from onion stems [88], _Bacillus altitudes_ DB26-R and _Bacillus subtilis_ subsp. _Inaquosorum_ B6-L from rice plants [89], and _Gluconacetobacter_ spp. from maize stems [90] are identified as potential bacteria involved not only in promoting plant growth but also in degrading pesticides. On the other hand, successful inoculation of these degradable microbes in the rhizosphere zone poses a big challenge [91].