ARRS J4-4556

Abstract

Soil quality is decreasing worldwide, due to erosion and intensive use of farmland. Crop plants are not adapted to reduced nutrient content, which is why we need to develop novel soil fertilization approaches delivering nutrients to the vicinity of the roots. In alpine oligotrophic soils mineral-weathering microbes accumulate in “hotspots” in the rhizosphere, in order to increase their efficiency and speed up the mineral dissolution process. Simulating this system, we will implement artificial encapsulation and immobilization of a microbial consortium incorporating mineral-weathering rhizobacteria, N2-fixators, degraders of olysaccharides, and strains for plant biocontrol, The bacteria will be immobilized onto surfaces of carriers to study their effect on nutrient release into the soil and promotion of plant growth.

Inoculation of bacteria into an agricultural systems is not simple and straightforward, but mostly inefficient, due to washing off, preadtion and competition. To solve these problems, we are proposing an approach, where the bacterial cells are locally concentrated by immobilization onto a protective carriers, mineral and organic, to form artificial nutrient-weathering "hotspots". Techniques like layer-by-layer (LBL) electrostatic deposition of charged polyelectrolytes and conventional entrapment into a polymer matrix will be implemented to modify the cell surface and to encapsulate and immobilize the cells. The proposed study will advance the general scientific knowledge on weathering bacteria, bacterial cell physiology and plant-microbe interactions, particularly by gaining more insight on the characteristics of the cell surface, cell division, growth and activity, bacterial cell-surface interactions and bacterial promotion of plant growth. The value of the proposed work is ground setting, will form the basis for future applicative solutions and will be transferable to other fields, like industrial biotechnology and medicine.

Povzetek

Kakovost tal se po vsem svetu slabša zaradi erozije in intenzivne rabe kmetijskih zemljišč. Kulturne rastline niso prilagojene na zmanjšano vsebnost hranil, zato moramo razviti nove pristope gnojenja tal, ki dovajajo hranila v bližino korenin. V alpskih oligotrofnih tleh se mikrobi, ki povzročajo preperevanje mineralov, kopičijo v "vročih točkah" v rizosferi, da bi povečali svojo učinkovitost in pospešili proces raztapljanja mineralov. S simulacijo tega sistema bomo izvedli umetno inkapsulacijo in imobilizacijo mikrobnega konzorcija, ki vključuje rizobakterije, ki lužijo hranila, N2-fiksatorje, razgrajevalce olisaharidov in seve za biokontrolo rastlin. Bakterije bodo imobilizirane na površine nosilcev, da se preuči njihov učinek na sproščanje hranil v tla in spodbujanje rasti rastlin.

Inokulacija bakterij v kmetijske sisteme ni enostaven postopek in je trenutno neučinkovit pristop zaradi izpiranja, predacije in kompeticije. Za rešitev teh težav predlagamo pristop, kjer se bakterijske celice lokalno koncentrirajo z imobilizacijo na zaščitne nosilce, mineralne in organske, da se oblikujejo umetne "vroče točke" za preperevanje hranil. Tehnike, kot je elektrostatično nanašanje po plasteh (LBL) nabitih polielektrolitov in konvencionalno ujetje v polimerno matriko, bodo uporabljene za spreminjanje celične površine ter za inkapsulacijo in imobilizacijo celic. Predlagana študija bo izboljšala splošno znanstveno razumevanje bakterijskega luženja hranil, fiziologije bakterijske celice in interakcij med rastlinami in mikrobi, zlasti s pridobitvijo boljšega vpogleda v značilnosti celične površine, delitev celic, rast in aktivnost, interakcije med celico in površino bakterij ter promocijo bakterij rasti rastlin. Dodana vrednost projekta je tudi v tem, da bodo pridobljeni rezultati predstavljali osnovo za prihodnje aplikativne rešitve ter da bodo prenosljivi na druga področja, kot sta industrijska biotehnologija in medicina.