Agricultural Microbiology Research Progress in India in the New Millennium

Abstract

The research efforts in microbiology over last two decades have focussed on assessing the microbial diversity in various soil types and cropping systems in all agro-eco-regions, including extreme environments resulting in creation of a vast repository of microorganisms, free living and endophytes. A marked departure from the past is their identification by both conventional and molecular methods, resulting in discovery of many novel species. The effects of various soil and agronomic management practices were assessed on soil microbial diversity and soil health by both classical and metagenomic approach. The beneficial effects of organic and integrated farming, and adverse effects of chemical intensification have been assessed, leading to the identification of actinobacteria as important players in maintaining soil health. A major impact has been the firm attention received from policy makers on the urgent need to conserve soil biodiversity and improve soil health. Identification of rapid methods of soil biological health assessment, improved rhizobial inoculants, microbial technology for rapid in situ and ex situ residue and waste breakdown, and mitigating climate change effects are the current priorities. Future priorities include assessment of the structure and function of the vast reservoir of unculturable microbes; deleterious microorganisms, assessment of soil-plant-microbe continuum and plant immunity modulation by microbes; rhizosphere engineering, role of archaea in maintaining soil health, microbial methods to improve soil organic matter formation; assessment and quantification of ecosystem services rendered by agriculturally important microorganisms; and improved microbial technology for biofertilizers and delivery systems. The tremendous advances in agricultural microbiology in last two decades in India are a cause for optimism that solutions will be forged for the above challenges using both classical and modern approaches, thereby ushering in the process more sustainable agricultural systems.

Agrochemical inputs and management have a greater impact on common bean rhizobia diversity than drought

“…Mineral fertilization reduces plant nodulation (Heath et al, 2010; Regus et al, 2016) and symbiotic e ciency (Gordon et al, 2016; Heath & Ti n, 2007; Rao et al, 2019; Weese et al, 2015) because it is energetically cheaper for plants to reduce ammonium and nitrate than to x N 2 , leading to a reduction on the presence and diversity of rhizobia over time (da-Silveira-Cardillo et al, 2019; Moreira et al, 2006). In the other hand, soil organic amendments, such as manure, increase the abundance and diversity of microorganisms and rhizobia (Li et al, 2022; Malhotra et al, 2015; Rao et al, 2019), promoting a greater plant nodulation(Herencia et al, 2020), as in our results (Fig.1and Fig.2).Consequently, the use of these agrochemicals leads to a loss of abundance and diversity in the soil microbiome(Rao et al, 2019), as well as of rhizobia (Silva Neto et al, 2013; Weese et al, 2015), as we observed in the conventional management plots with reduction in plant nodulation (Table…”

“…1-2) ( We also found lower abundance and diversity in the soil microbiome in conventional managements plots even before sowing and under irrigated conditions (Table 3). This would be related to the practices and agrochemicals used in conventional agriculture (Rao et al, 2019), since the two sampled agricultural soils, conventional and organic, had similar climatic conditions and both presented similar cropping histories and similar soil characteristics (Table 2).…”

Evaluation of genotypes and correlation studies in Marigold (Tagetes spp.) for growth and yield attributes

“…reported that variation in days taken to flowering is attributed to genetic makeup of various germplasm lines. Moreover, due to favorable climatic conditions there is more dry matter accumulation which favors early flowering in marigold (Rao and Reddy, 2002).…”

Microbiology in India: status, challenges and scope

“…Only by identifying the primary areas of research and development within distinct agricultural sectors can the concerns of overpopulation and food security be addressed (Singh et al, 2016). As a result, over the last two decades, agricultural microbiology research has focused on assessing microbial diversity in a variety of soil types and cropping systems across all agro-ecoregions, including extreme environments, resulting in the creation of a vast repository of microorganisms, free-living and endophytes (Rao et al, 2019). The use of microorganisms, their enzymatic machinery, or their products in bioremediation technology gives hope for a long-term, cost-effective technique of mitigating and turning contaminants harmless through natural biological processes.…”

“…To target the uncharted depths of microbial existence and persistence, microbes especially bacteria have been isolated from various chemically contaminated sites (Mukherjee et al ., 2013; Singh et al ., 2013; Kumar et al ., 2015; Verma et al ., 2015) and extremophilic areas (Dwivedi et al ., 2015; Sharma et al ., 2018; Sood et al ., 2021a). Another major impact of microbiological research in India is on the identification of rapid methods of soil biological health assessment, microbial technology for rapid in situ and ex situ residue, and waste breakdown (Rao et al ., 2019). Indian microbiologists are taking advantage of the technological advancements in DNA sequencing and computational biology that have opened new fields of inquiry, particularly in genomics and metagenomics (Kumar et al ., 2013; Sangwan et al ., 2014; Verma et al ., 2014; Kumar et al ., 2017; Nagar et al ., 2020).…”