Transcriptome changes during early developlemntal stages of maize (Zea mays L.) caused by low-temperature stress

[M. Božić]

197 str.

BIOLOGIJA - MOLEKULARNA GENETIKA BILJAKA / BIOLOGY - PLANT MOLECULAR GENETICS

Kukuruz je jedan od najznačajnijih i najšire gajenih useva. Međutim, kukuruz je i jedna od vrsta najosetljivijih na negativne faktore životne sredine izazvane klimatskim promenama. Stoga su razvijene brojne strategije sa ciljem ublažavanja uticaja klimatskih promena na proizvodnju navedenog useva. S obzirom da kukuruz gajen u umerenim oblastima dostiže vegetativne faze najosetljivije na visoke temperature i sušu (cvetanje i nalivanje zrna) u doba godine kada se navedeni klimatski ekstremi dešavaju, rana setva se izdvaja kao jedna od najperspektivnijih strategija održavanja visokog prinosa i proizvodnje. Ipak, rana setva znači i izlaganje biljaka kukuruza niskim temperaturama (NT) u ranim fazama razvića, odnosno u fazi nicanja (VE). Stoga je neophodno dobro poznavanje mehanizama koji su u osnovi odgovora i razvijanja tolerantnosti na NT u ranim fazama razvića kukuruza. Da bi se navedeni cilj postigao, urađeno je sekvenciranje ukupnog transkriptoma dve linije kukuruza konstrastne tolerantnosti na NT (LS i LT) u fazi klijanaca starih pet dana. Izolacija RNK i sekvenciranje su urađeni nakon 6h i 24h tretmana niskim temperaturama (10/8°C). Isto je urađeno za kontrolne klijance gajene u optimalnim uslovima (25°/20°C). Dobijeni sirovi podaci o sekvencama su podvrgnuti proveri kvaliteta i mapiranju na referentni genom, i urađene su specifične analize za svaku od ispitanih klasa RNK – informacione (geni), duge nekodirajuće (lncRNK), cirkularne (circRNK) i mikroRNK (miRNK). Takođe su predviđene i potencijalne interakcije između navedenih klasa RNK i konstruisana je mreža interakcija. Pronađeno je ukupno 508 diferencijalno eksprimiranih gena, 63 lncRNK i 649 miRNK između kontrole i tretmana. circRNK nisu bile uključene u odgovor na niske temperature u VE fazi kukuruza. Na osnovu ekspresije gena, lncRNK i miRNK pokazano je da su niske temperature negativno uticale na fotosintetske procese i stabilizaciju proteina. Takođe, razlika između genotipova je uočena kroz odbrambene reakcije na ove promene, što ukazuje da bi oni mogli biti od značaja za uspostavljanje tolerantnosti na NT.

Maize is one of the most important and widely cultivated agricultural crops. However, it is also one of the species most sensitive to negative environmental factors caused by climate change. Therefore, numerous strategies have been developed with the aim of mitigating the impact of climate change on the production of this crop. Given that maize grown in temperate areas reaches the stages most sensitive to high temperatures and drought (flowering and grain filling) at the time of year when these climate extremes occur, early sowing stands out as one of the most promising strategies for ensuring high yield and production. However, it also means exposing maize plants to low temperatures (LT) during the early stages of development, i.e. the emergence stage (VE). Therefore, understanding the mechanisms underlying the response and establishing of tolerance to LT in the early stages of maize development is of great importance. In order to achieve this, whole transcriptome sequencing of two maize lines of contrasting tolerance to LT (LS and LT) was performed at the stage five-day-old seedling stage. RNA isolation and sequencing were performed after 6h and 24h of low-temperature treatment (10/8°C). The same was done for control seedlings grown in optimal conditions (25°/20°C). The sequence data was then subjected to quality control and mapping to the reference genome, and specific analyses were performed for each of the investigated RNA classes – messenger (genes), long non-coding (lncRNA), circular (circRNA) and microRNA (miRNA). Potential interactions between the examined classes of RNA were also predicted and an interaction network was constructed. A total of 508 differentially expressed genes, 63 lncRNAs and 649 miRNAs were found between control and treatment. circRNAs were not involved in the low-temperature response of maize in the VE stage. Based on the expression of genes, lncRNA and miRNA, it was shown that low temperatures negatively affected photosynthetic processes and protein stabilization. Also, the difference between the genotypes was observed through the defense reactions to these changes, which indicates that they could be important for the establishment of LT tolerance.

Klimatske promene, kukuruz (Zea mays L.), odgovor na stres niskih temperatura, analiza transkriptoma

Climate change, maize (Zea mays L.), low-temperature stress response, whole transcriptome profiling

577.2:582.546.61(043.3)

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