Rhizosphere to Rhizosphere Hybridization in Fruit Crops: New Perspectives

Anoop Kumar Srivastava^1*Seyed Majid Mousavi²Popy - Bora^3*Debashish Hota⁴Vikramaditya - Pandey⁵Suresh Kumar Malhotra^6*Vasileios Ziogas⁷

• ¹Central Citrus Research Institute (ICAR), Nagpur, India
• ²Soil & Water Research Institute, Karaj, Alborz, Iran
• ³Assam Agricultural University, Jorhat, Assam, India
• ⁴Siksha O Anusandhan University, Bhubaneswar, Odisha, India
• ⁵Indian Council of Agricultural Research (ICAR), New Delhi, Delhi, India
• ⁶Maharana Pratap Horticultural University, Anjanthali, Haryana, India
• ⁷Hellenic Agricultural Organization – ELGO, Athens, Greece

Rhizosphere is the playground of multiple microbial functions marked by phenotypical, physiological, and molecular crop responses. For better understanding on of the rhizosphere microbiome, nextgeneration sequencing has shifted research priorities from microbe specific function(s) to microbiome regulations with emphasis on multi-functional microbes. Such an attempt has opened two prime concepts viz., identifying microbial antagonists (between beneficial microbes and plant pathogens) from predominant stock of plant growth promoting microbes, preferably in a consortia mode towards better bioprospecting of soil-plant health, and secondly, developing microbially a more active rhizosphere through a process called rhizosphere hybridization (RH). The present review is focused on some recent studies on the outcome of RH in citrus cultivars showing renewed functional corridors of rhizosphere characterized by secondary metabolites load supporting functional dichotomy through elevated nutrient-supply, activated soil enzymes profile, improvements in root-shoot system, and plant defense enzymes. These response trade-offs collectively contributed to higher quality yield coupled with possibly a better shelf life of fruits. The rhizobiome of heritage trees viz., Azadirachta, Ficus, Dendrocalamus, Populus, Sasa, Acer, Alnus, Quercus, and Phyllostachys could be effectively used in exercising RH. These observations on RH have put forth some exciting prospects in expanding the concept in other fruit crops with emphasis on developing a robust holobiont ( climate-smart suppressive soils and engineering rhizosphere microbiome for microbially engineered plants) as a part of regenerative agriculture.